As Corion remarks above, you should try and reduce the problem (script) to a bare minimum, just enought to demonstrate the problem. That would make it easier for you to spot the error, and it would make it a more tempting problem for others to try and help with. Not least because it would demonstrate some effort on your part.

Still, I will give you a pointer:

while (my $row = $_read_sth->fetchall_arrayref)
{
    # What's inside $row?
    use Data::Dumper;
    print Dumper( \$row ) and exit;
    # take a close look at the output
[download]

You might want to take a look at the docs: http://search.cpan.org/~timb/DBI/DBI.pm#fetchall_arrayref

keep up the spirit!