The LWP::Debug module can help you watch what's going on.

However, the problem might not be with your Perl script. The problem might be on the other side. Can you connect to that CGI script manually? Are you allowed to (maybe you're now blocked)? What happens when you try the same thing without using your CGI script?

As an aside, I usually find phrases like "nothing has changed" and "I did nothing" to mean just the opposite. :)