I inserted debugging code. It's failing in the OTHER place you're calling netanswer:

sub error
    {
    my ($i);

    for($i=0;$i<$c_NUMTRAIN;$i++) {
    print "netanswer called from error()\n";
    &netanswer($actafer[$i]);
   # $ecm[$i]=ec(\@{$desout[$i]},\@z,$c_OUT);
    $ecm[$i]=ec($i,$c_OUT);
    }
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There, you're just passing it $actafer[$i], which is an array reference instead of a value. The array reference then gets turned into an absurdly high index, and perl attempts to expand the array to that big, and fails. Fix error(), and the problem will go away.