Think CGI isn't working? Try this.
Here is a small test script that you should be able to upload to your directory, chmod (change permissions) to 755 and then access via the web to see if an account's cgi access is working.
print "Content-Type: text/html\n\n";
print "All is working. :)";
You may put the above code into a .cgi file or a .pl file. If you get a 500 internal error, then check to make sure you uploaded it in ascii mode and that it's been given the correct permissions. If you're sure everything is correct, then please send in a helpdesk ticket with the url to this test script you uploaded to that account.
Note: Please also read the SuExec knowledgebase article as this is enabled on all servers and with SuExec turned on, you may need to set permissions differently than what your script's instructions tell you to.