...are you sure this is the code you have? $xml isn't submitted to the server at all. Of course, the script also complains about the declaration of $res. As a side note, please tell me that http is a typo and should actually be https. Otherwise you are sending complete credit card information across the internet in plain text.

Please change the code so we can help. :)

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1