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.
in reply to Please help..
Still, I will give you a pointer:
while (my $row = $_read_sth->fetchall_arrayref)
# What's inside $row?
print Dumper( \$row ) and exit;
# take a close look at the output
You might want to take a look at the docs:
keep up the spirit!