r - plm::pgmm() Error in yX[[1]] : subscript out of bounds -

in r, encountering error using pgmm() function in plm package can't resolve through debugging. here call results in error:

emp.gmm = pgmm(growth ~ lgdp_pc + lschool |    lag(lgdp_pc,2),    data=temp1.subset,    effect='twoways', model='twosteps') 

the error message is:

error in yx[[1]] : subscript out of bounds in addition: warning message: in `[.data.frame`(index, as.numeric(rownames(mf)), ) :   nas introduced coercion 

this structure of data frame temp1.subset, using dput():

structure(list(growth = structure(c(nan, nan, nan, nan, -0.000154495239257812,  -0.0161255836486816, -0.0161551475524902, 0.0574196815490723,  0.0497237205505371, 0.0457057952880859, nan, nan, -0.0703577995300293,  0.0167842864990234, -0.0930408477783203, -0.0327302932739258,  -0.0194591522216797, -0.00672683715820313, 0.0186029434204102,  0.0169768333435059, 0.0181658267974854, 0.0245670318603516, 0.0144176483154297,  0.0118904113769531, -0.0398967742919922, -0.0192060470581055,  0.0499397277832031, 0.013348388671875, 0.0102230072021484, 0.0554094314575195,  nan, nan, nan, nan, nan, nan, -0.108685398101807, 0.0593433380126953,  0.116020393371582, 0.0333575248718262, nan, 0.0355857849121094,  0.0102117538452148, 0.0167465209960938, 0.013456916809082, 0.0224128723144531,  0.0125150680541992, 0.0307027816772461, 0.0188102722167969, 0.0116562843322754,  0.0342285633087158, 0.0463666915893555, 0.035101318359375, 0.0326730728149414,  0.0143096923828125, 0.0243467330932617, 0.014262580871582, 0.027958869934082,  0.0103265762329102, 0.0110832214355469, 0.0390259027481079, 0.0521463394165039,  -0.00384244918823242, 0.0173358917236328, 0.0171653747558594,  0.00626802444458008, -0.0418449401855469, -0.0240262985229492,  -0.00464649200439453, 0.0116527557373047, 0.0413355827331543,  0.0421024322509766, 0.0318218231201172, 0.0301837921142578, 0.00917606353759766,  0.0281953811645508, 0.0124330520629883, 0.0258995056152344, 0.0112407684326172,  0.00453147888183594, 0.0137679576873779, 0.00525884628295898,  -0.0108115196228027, 0.0126751899719238, 0.0149676322937012,  -0.0217413902282715, 0.00618104934692383, 0.0217741966247559,  0.00468902587890625, 0.00880584716796875, 0.0183011293411255,  0.00738563537597656, -0.0515353202819824, 0.014140796661377,  0.0103920936584473, 0.0134731292724609, 0.0225117683410645, 0.0319003105163574,  0.036073112487793, 0.0455719947814941, nan, nan, nan, nan, 0.0311300277709961,  0.0200127601623535, -0.0190550804138184, 0.010537052154541, 0.0614358901977539,  0.0308845520019531, nan, nan, nan, nan, -0.049329948425293, 0.00992908477783203,  0.0339340209960938, 0.0186641693115234, 0.0365270614624023, 0.0473820368448893 ), .names = c("alb-1961", "alb-1966", "alb-1971", "alb-1976",  "alb-1981", "alb-1986", "alb-1991", "alb-1996", "alb-2001", "alb-2006",  "are-1961", "are-1966", "are-1971", "are-1976", "are-1981", "are-1986",  "are-1991", "are-1996", "are-2001", "are-2006", "arg-1961", "arg-1966",  "arg-1971", "arg-1976", "arg-1981", "arg-1986", "arg-1991", "arg-1996",  "arg-2001", "arg-2006", "arm-1961", "arm-1966", "arm-1971", "arm-1976",  "arm-1981", "arm-1986", "arm-1991", "arm-1996", "arm-2001", "arm-2006",  "aus-1961", "aus-1966", "aus-1971", "aus-1976", "aus-1981", "aus-1986",  "aus-1991", "aus-1996", "aus-2001", "aus-2006", "aut-1961", "aut-1966",  "aut-1971", "aut-1976", "aut-1981", "aut-1986", "aut-1991", "aut-1996",  "aut-2001", "aut-2006", "bdi-1961", "bdi-1966", "bdi-1971", "bdi-1976",  "bdi-1981", "bdi-1986", "bdi-1991", "bdi-1996", "bdi-2001", "bdi-2006",  "bel-1961", "bel-1966", "bel-1971", "bel-1976", "bel-1981", "bel-1986",  "bel-1991", "bel-1996", "bel-2001", "bel-2006", "ben-1961", "ben-1966",  "ben-1971", "ben-1976", "ben-1981", "ben-1986", "ben-1991", "ben-1996",  "ben-2001", "ben-2006", "bgd-1961", "bgd-1966", "bgd-1971", "bgd-1976",  "bgd-1981", "bgd-1986", "bgd-1991", "bgd-1996", "bgd-2001", "bgd-2006",  "bgr-1961", "bgr-1966", "bgr-1971", "bgr-1976", "bgr-1981", "bgr-1986",  "bgr-1991", "bgr-1996", "bgr-2001", "bgr-2006", "bhr-1961", "bhr-1966",  "bhr-1971", "bhr-1976", "bhr-1981", "bhr-1986", "bhr-1991", "bhr-1996",  "bhr-2001", "bhr-2006")), lgdp_pc = structure(c(na, na, na, na,  7.00262928009033, 6.99529218673706, 6.53417539596558, 6.90051984786987,  7.15865516662598, 7.38541603088379, na, na, na, 10.6491794586182,  10.69615650177, 10.018406867981, 10.0704908370972, 10.0255823135376,  9.95373916625977, 10.1316347122192, 8.60022068023682, 8.65194797515869,  8.83529758453369, 8.8311882019043, 8.85401916503906, 8.78915596008301,  8.73702239990234, 8.92235565185547, 8.89288139343262, 9.07096481323242,  na, na, na, na, na, na, 6.56363916397095, 6.20834350585938, 6.52715730667114,  7.13503837585449, na, 9.28063583374023, 9.46360492706299, 9.52500152587891,  9.61036205291748, 9.69009971618652, 9.75651931762695, 9.8624963760376,  9.9943208694458, 10.0977354049683, 8.96818256378174, 9.15271186828613,  9.38222980499268, 9.55772018432617, 9.67277145385742, 9.76892948150635,  9.89057159423828, 9.96095561981201, 10.0814599990845, 10.1612281799316,  4.42424869537354, 4.60615253448486, 4.85785865783691, 4.88180637359619,  4.99203109741211, 4.99264097213745, 5.05267095565796, 4.72422027587891,  4.69666385650635, 4.69302225112915, 8.96421718597412, 9.15429973602295,  9.37329006195068, 9.55253601074219, 9.64679527282715, 9.71363735198975,  9.85140705108643, 9.91110229492188, 10.0330429077148, 10.1047925949097,  5.62822294235229, 5.69843626022339, 5.67156982421875, 5.63838481903076,  5.78506278991699, 5.78611755371094, 5.69635629653931, 5.73845529556274,  5.84113121032715, 5.85585737228394, 5.49890518188477, 5.5727391242981,  5.52636432647705, 5.3795313835144, 5.43264722824097, 5.4912257194519,  5.55287218093872, 5.67962026596069, 5.84709310531616, 6.04283237457275,  na, na, na, na, 7.21125555038452, 7.36029720306396, 7.342613697052,  7.23626947402954, 7.43780517578125, 7.75390672683716, na, na,  na, na, 9.25457572937012, 9.07840728759766, 9.22368812561035,  9.33519268035889, 9.43653678894043, 9.64009284973145), .names = c("alb-1961",  "alb-1966", "alb-1971", "alb-1976", "alb-1981", "alb-1986", "alb-1991",  "alb-1996", "alb-2001", "alb-2006", "are-1961", "are-1966", "are-1971",  "are-1976", "are-1981", "are-1986", "are-1991", "are-1996", "are-2001",  "are-2006", "arg-1961", "arg-1966", "arg-1971", "arg-1976", "arg-1981",  "arg-1986", "arg-1991", "arg-1996", "arg-2001", "arg-2006", "arm-1961",  "arm-1966", "arm-1971", "arm-1976", "arm-1981", "arm-1986", "arm-1991",  "arm-1996", "arm-2001", "arm-2006", "aus-1961", "aus-1966", "aus-1971",  "aus-1976", "aus-1981", "aus-1986", "aus-1991", "aus-1996", "aus-2001",  "aus-2006", "aut-1961", "aut-1966", "aut-1971", "aut-1976", "aut-1981",  "aut-1986", "aut-1991", "aut-1996", "aut-2001", "aut-2006", "bdi-1961",  "bdi-1966", "bdi-1971", "bdi-1976", "bdi-1981", "bdi-1986", "bdi-1991",  "bdi-1996", "bdi-2001", "bdi-2006", "bel-1961", "bel-1966", "bel-1971",  "bel-1976", "bel-1981", "bel-1986", "bel-1991", "bel-1996", "bel-2001",  "bel-2006", "ben-1961", "ben-1966", "ben-1971", "ben-1976", "ben-1981",  "ben-1986", "ben-1991", "ben-1996", "ben-2001", "ben-2006", "bgd-1961",  "bgd-1966", "bgd-1971", "bgd-1976", "bgd-1981", "bgd-1986", "bgd-1991",  "bgd-1996", "bgd-2001", "bgd-2006", "bgr-1961", "bgr-1966", "bgr-1971",  "bgr-1976", "bgr-1981", "bgr-1986", "bgr-1991", "bgr-1996", "bgr-2001",  "bgr-2006", "bhr-1961", "bhr-1966", "bhr-1971", "bhr-1976", "bhr-1981",  "bhr-1986", "bhr-1991", "bhr-1996", "bhr-2001", "bhr-2006")),      lschool = structure(c(2.35911043320897, 2.41328221003299,      2.43590717090892, 2.52054220466727, 2.61560503855615, 2.72324801900766,      2.83683622695474, 2.92239366844159, 2.98478811604867, 3.01831974280998,      1.13164763254923, 1.37516821020743, 1.59886060402446, 1.80547476073608,      1.98913287448312, 2.20432184655087, 2.42784075369646, 2.65588366696786,      2.81063046469833, 2.86877440588403, 2.37400357050429, 2.42441204771293,      2.47798706926758, 2.55828772353817, 2.60388133600267, 2.70318329199619,      2.75915780984862, 2.81559988032215, 2.84357013976038, 2.87898832384181,      2.69861402431441, 2.77088423462735, 2.80632117955809, 2.85885783549437,      2.90995708560811, 2.95520102086794, 3.0053685417, 3.03999882510887,      3.07462396270553, 3.07415132254071, 2.90252699435189, 2.9280081666637,      2.99215965536795, 3.06980931923238, 3.14481445700899, 3.14568662948742,      3.15745159513512, 3.16565452292317, 3.16828962011402, 3.17444030770882,      2.03112275156487, 2.31962774860704, 2.50347571143773, 2.60055782875909,      2.6700354985435, 2.73118986769993, 2.79037936837915, 2.84235518076037,      2.89346188939731, 2.94574956915881, 0.371049757087941, 0.51206693783937,      0.627845785629485, 0.783645777671808, 0.9415377508948, 1.08388016710258,      1.15957326239976, 1.23771094110347, 1.36416678484992, 1.55860608884099,      2.58883096646545, 2.61478494877199, 2.6419320829608, 2.71831452216391,      2.78024406563142, 2.8332995985595, 2.93560084277246, 2.96949570689101,      3.00250899118587, 3.05544722221461, 0.563242558294602, 0.577648182586872,      0.589770022828634, 0.600824720233934, 0.610268370419734,      0.942916093580047, 1.27316622595578, 1.507842949318, 1.66976299411005,      1.78948811100657, 0.814008942248105, 0.940630166333027, 0.986379162392978,      1.00654720426646, 1.43249756506825, 1.61045927447873, 1.77434651166291,      1.91274715868216, 2.01638845451714, 2.13897075551214, 2.44272816515807,      2.48913484536694, 2.63313959583549, 2.70669315556332, 2.77951244261718,      2.84203624922508, 2.87808041892673, 2.92586417117872, 2.93660703930988,      2.96557257930554, 0.946515634474934, 1.08185063283973, 1.38593695739655,      1.71597017604808, 2.11544628015034, 2.35380472337687, 2.49719881809782,      2.66522232693863, 2.81655202001251, 2.8931032318686), .names = c("alb-1961",      "alb-1966", "alb-1971", "alb-1976", "alb-1981", "alb-1986",      "alb-1991", "alb-1996", "alb-2001", "alb-2006", "are-1961",      "are-1966", "are-1971", "are-1976", "are-1981", "are-1986",      "are-1991", "are-1996", "are-2001", "are-2006", "arg-1961",      "arg-1966", "arg-1971", "arg-1976", "arg-1981", "arg-1986",      "arg-1991", "arg-1996", "arg-2001", "arg-2006", "arm-1961",      "arm-1966", "arm-1971", "arm-1976", "arm-1981", "arm-1986",      "arm-1991", "arm-1996", "arm-2001", "arm-2006", "aus-1961",      "aus-1966", "aus-1971", "aus-1976", "aus-1981", "aus-1986",      "aus-1991", "aus-1996", "aus-2001", "aus-2006", "aut-1961",      "aut-1966", "aut-1971", "aut-1976", "aut-1981", "aut-1986",      "aut-1991", "aut-1996", "aut-2001", "aut-2006", "bdi-1961",      "bdi-1966", "bdi-1971", "bdi-1976", "bdi-1981", "bdi-1986",      "bdi-1991", "bdi-1996", "bdi-2001", "bdi-2006", "bel-1961",      "bel-1966", "bel-1971", "bel-1976", "bel-1981", "bel-1986",      "bel-1991", "bel-1996", "bel-2001", "bel-2006", "ben-1961",      "ben-1966", "ben-1971", "ben-1976", "ben-1981", "ben-1986",      "ben-1991", "ben-1996", "ben-2001", "ben-2006", "bgd-1961",      "bgd-1966", "bgd-1971", "bgd-1976", "bgd-1981", "bgd-1986",      "bgd-1991", "bgd-1996", "bgd-2001", "bgd-2006", "bgr-1961",      "bgr-1966", "bgr-1971", "bgr-1976", "bgr-1981", "bgr-1986",      "bgr-1991", "bgr-1996", "bgr-2001", "bgr-2006", "bhr-1961",      "bhr-1966", "bhr-1971", "bhr-1976", "bhr-1981", "bhr-1986",      "bhr-1991", "bhr-1996", "bhr-2001", "bhr-2006"))), .names = c("growth",  "lgdp_pc", "lschool"), class = c("pdata.frame", "data.frame"), row.names = c("alb-1961",  "alb-1966", "alb-1971", "alb-1976", "alb-1981", "alb-1986", "alb-1991",  "alb-1996", "alb-2001", "alb-2006", "are-1961", "are-1966", "are-1971",  "are-1976", "are-1981", "are-1986", "are-1991", "are-1996", "are-2001",  "are-2006", "arg-1961", "arg-1966", "arg-1971", "arg-1976", "arg-1981",  "arg-1986", "arg-1991", "arg-1996", "arg-2001", "arg-2006", "arm-1961",  "arm-1966", "arm-1971", "arm-1976", "arm-1981", "arm-1986", "arm-1991",  "arm-1996", "arm-2001", "arm-2006", "aus-1961", "aus-1966", "aus-1971",  "aus-1976", "aus-1981", "aus-1986", "aus-1991", "aus-1996", "aus-2001",  "aus-2006", "aut-1961", "aut-1966", "aut-1971", "aut-1976", "aut-1981",  "aut-1986", "aut-1991", "aut-1996", "aut-2001", "aut-2006", "bdi-1961",  "bdi-1966", "bdi-1971", "bdi-1976", "bdi-1981", "bdi-1986", "bdi-1991",  "bdi-1996", "bdi-2001", "bdi-2006", "bel-1961", "bel-1966", "bel-1971",  "bel-1976", "bel-1981", "bel-1986", "bel-1991", "bel-1996", "bel-2001",  "bel-2006", "ben-1961", "ben-1966", "ben-1971", "ben-1976", "ben-1981",  "ben-1986", "ben-1991", "ben-1996", "ben-2001", "ben-2006", "bgd-1961",  "bgd-1966", "bgd-1971", "bgd-1976", "bgd-1981", "bgd-1986", "bgd-1991",  "bgd-1996", "bgd-2001", "bgd-2006", "bgr-1961", "bgr-1966", "bgr-1971",  "bgr-1976", "bgr-1981", "bgr-1986", "bgr-1991", "bgr-1996", "bgr-2001",  "bgr-2006", "bhr-1961", "bhr-1966", "bhr-1971", "bhr-1976", "bhr-1981",  "bhr-1986", "bhr-1991", "bhr-1996", "bhr-2001", "bhr-2006"), index = structure(list(     wbcode = structure(c(5l, 5l, 5l, 5l, 5l, 5l, 5l, 5l, 5l,      5l, 7l, 7l, 7l, 7l, 7l, 7l, 7l, 7l, 7l, 7l, 8l, 8l, 8l, 8l,      8l, 8l, 8l, 8l, 8l, 8l, 9l, 9l, 9l, 9l, 9l, 9l, 9l, 9l, 9l,      9l, 12l, 12l, 12l, 12l, 12l, 12l, 12l, 12l, 12l, 12l, 13l,      13l, 13l, 13l, 13l, 13l, 13l, 13l, 13l, 13l, 15l, 15l, 15l,      15l, 15l, 15l, 15l, 15l, 15l, 15l, 16l, 16l, 16l, 16l, 16l,      16l, 16l, 16l, 16l, 16l, 17l, 17l, 17l, 17l, 17l, 17l, 17l,      17l, 17l, 17l, 19l, 19l, 19l, 19l, 19l, 19l, 19l, 19l, 19l,      19l, 20l, 20l, 20l, 20l, 20l, 20l, 20l, 20l, 20l, 20l, 21l,      21l, 21l, 21l, 21l, 21l, 21l, 21l, 21l, 21l), .label = c("abw",      "ado", "afg", "ago", "alb", "arb", "are", "arg", "arm", "asm",      "atg", "aus", "aut", "aze", "bdi", "bel", "ben", "bfa", "bgd",      "bgr", "bhr", "bhs", "bih", "blr", "blz", "bmu", "bol", "bra",      "brb", "brn", "btn", "bwa", "caf", "can", "che", "chi", "chl",      "chn", "civ", "cmr", "cog", "col", "com", "cpv", "cri", "cub",      "cuw", "cym", "cyp", "cze", "deu", "dji", "dma", "dnk", "dom",      "dza", "eap", "eas", "eca", "ecs", "ecu", "egy", "emu", "eri",      "esp", "est", "eth", "euu", "fin", "fji", "fra", "fro", "fsm",      "gab", "gbr", "geo", "gha", "gib", "gin", "gmb", "gnb", "gnq",      "grc", "grd", "grl", "gtm", "gum", "guy", "hic", "hkg", "hnd",      "hpc", "hrv", "hti", "hun", "idn", "imy", "ind", "irl", "irn",      "irq", "isl", "isr", "ita", "jam", "jor", "jpn", "kaz", "ken",      "kgz", "khm", "kir", "kna", "kor", "ksv", "kwt", "lac", "lao",      "lbn", "lbr", "lby", "lca", "lcn", "ldc", "lic", "lie", "lka",      "lmc", "lmy", "lso", "ltu", "lux", "lva", "mac", "maf", "mar",      "mco", "mda", "mdg", "mdv", "mea", "mex", "mhl", "mic", "mkd",      "mli", "mlt", "mmr", "mna", "mne", "mng", "mnp", "moz", "mrt",      "mus", "mwi", "mys", "myt", "nac", "nam", "ncl", "ner", "nga",      "nic", "nld", "noc", "nor", "npl", "nzl", "oec", "oed", "omn",      "pak", "pan", "per", "phl", "plw", "png", "pol", "pri", "prk",      "prt", "pry", "pyf", "qat", "rom", "rus", "rwa", "sas", "sau",      "sdn", "sen", "sgp", "slb", "sle", "slv", "smr", "som", "srb",      "ssa", "ssf", "stp", "sur", "svk", "svn", "swe", "swz", "sxm",      "syc", "syr", "tca", "tcd", "tgo", "tha", "tjk", "tkm", "tmp",      "ton", "tto", "tun", "tur", "tuv", "tza", "uga", "ukr", "umc",      "ury", "usa", "uzb", "vct", "ven", "vir", "vnm", "vut", "wbg",      "wld", "wsm", "yem", "zaf", "zar", "zmb", "zwe"), class = "factor"),      year = structure(c(1l, 6l, 11l, 16l, 21l, 26l, 31l, 36l,      41l, 46l, 1l, 6l, 11l, 16l, 21l, 26l, 31l, 36l, 41l, 46l,      1l, 6l, 11l, 16l, 21l, 26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l,      16l, 21l, 26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l, 16l, 21l,      26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l, 16l, 21l, 26l, 31l,      36l, 41l, 46l, 1l, 6l, 11l, 16l, 21l, 26l, 31l, 36l, 41l,      46l, 1l, 6l, 11l, 16l, 21l, 26l, 31l, 36l, 41l, 46l, 1l,      6l, 11l, 16l, 21l, 26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l,      16l, 21l, 26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l, 16l, 21l,      26l, 31l, 36l, 41l, 46l, 1l, 6l, 11l, 16l, 21l, 26l, 31l,      36l, 41l, 46l), .label = c("1961", "1962", "1963", "1964",      "1965", "1966", "1967", "1968", "1969", "1970", "1971", "1972",      "1973", "1974", "1975", "1976", "1977", "1978", "1979", "1980",      "1981", "1982", "1983", "1984", "1985", "1986", "1987", "1988",      "1989", "1990", "1991", "1992", "1993", "1994", "1995", "1996",      "1997", "1998", "1999", "2000", "2001", "2002", "2003", "2004",      "2005", "2006", "2007", "2008", "2009", "2010"), class = "factor")), .names = c("wbcode",  "year"), row.names = c("201", "206", "211", "216", "221", "226",  "231", "236", "241", "246", "301", "306", "311", "316", "321",  "326", "331", "336", "341", "346", "351", "356", "361", "366",  "371", "376", "381", "386", "391", "396", "401", "406", "411",  "416", "421", "426", "431", "436", "441", "446", "551", "556",  "561", "566", "571", "576", "581", "586", "591", "596", "601",  "606", "611", "616", "621", "626", "631", "636", "641", "646",  "701", "706", "711", "716", "721", "726", "731", "736", "741",  "746", "751", "756", "761", "766", "771", "776", "781", "786",  "791", "796", "801", "806", "811", "816", "821", "826", "831",  "836", "841", "846", "901", "906", "911", "916", "921", "926",  "931", "936", "941", "946", "951", "956", "961", "966", "971",  "976", "981", "986", "991", "996", "1001", "1006", "1011", "1016",  "1021", "1026", "1031", "1036", "1041", "1046"), class = c("pindex",  "data.frame"))) 

my sessioninfo() is:

r version 3.0.1 (2013-05-16) platform: i386-w64-mingw32/i386 (32-bit) 

i think weird behaviour happens around these lines in function pgmm():

data <- eval(mf, parent.frame()) index <- index(data) 

when generated, object data seems have correct 'index' attribute, when index(data) executed, attribute set null. may have call rownames(mf).