I take it that the error that you are getting coming from your web server that your perl script is running on as a CGI. If so, look at the server's error log to see what error message perl itself generated.

How are you reading $txtque (the one outside of the for loop) into memory in the first place? If it it coming from a file, you might try this:

open my $fh, '<', '/the/file/with/txtque'
  or die "unable to open ...: $!\n";
{
  local($/) = '~';
  while (my $txtque = <$fh>) {
    my $count = $dbh->do(...); # execute the INSERT statement here
  }
}
[download]

That is, read in one $txtque value at a time and execute the INSERT statement instead of reading in all of the $txtque values in before doing the inserts.