Check the following:

1) Is your web server setup to handle .cgi files?
2) Do you have the #!perl at the top of the script?
    (you have to have perl in path for that to work, if
     you don't have perl in your path use the full path.
     I recommend having it in your path.  ActiveState Perl
     adds it by default.)
3) Are you printing the correct header?
4) Look in the error log for the error message. This will
hopefully contain useful information.

If you are still having trouble post some of the code you are trying to get going.