As gellyfish mentioned, there's a lack of data that can really help you. I would first off recommend you take a look at the links offered at Intro to the Monastery to get an idea of the best way to ask for help. It's not 'cause we're snobbish, but simply so that folks don't have to spend time doing what I'm about to do in the next paragraph: Guess at Your Situation. Plus, you don't have to play "guess what we need" quite so much, so you and we all win! So, the questions/comments:

1. If you're not, Use CGI.pm. REALLY.
2. What is the name of your editing program?
3. What OS and Web Server are you using?
4. Are you sending a header with your code? (CGI.pm makes sending headers dead easy!)
5. Have you the correct permissions for the code?

That error tends to come with bad, or no, headers being sent with your program. And that's one of many possible issues. You might want to also Google for that error; it's a very common one that has little, sometimes, to do with Perl, and a lot to do with how your Web Server serves up CGI (which is lanaguage-neutral).

Finally, a few (thousand) words from Ovid:

• use CGI or die;, and
• Ovid's CGI Course

Does any of this help?