Depending on which version of perl you got, you will get one of the following from perldoc -q 500

My CGI script runs from the command line but not the browser.  (500 Server Error)
          Several things could be wrong. You can go through the
          "Troubleshooting Perl CGI scripts" guide at

                  http://www.perl.org/troubleshooting_CGI.html

          If, after that, you can demonstrate that you've read the FAQs
          and that your problem isn't something simple that can be easily
          answered, you'll probably receive a courteous and useful reply
          to your question if you post it on
          comp.infosystems.www.authoring.cgi (if it's something to do with
          HTTP or the CGI protocols). Questions that appear to be Perl
          questions but are really CGI ones that are posted to
          comp.lang.perl.misc are not so well received.

          The useful FAQs, related documents, and troubleshooting guides
          are listed in the CGI Meta FAQ:

                  http://www.perl.org/CGI_MetaFAQ.html

older

 My CGI script runs from the command line but not the browser.  (500 Server Error)
           If you can demonstrate that you've read the following FAQs and
           that your problem isn't something simple that can be easily
           answered, you'll probably receive a courteous and useful reply
           to your question if you post it on
           comp.infosystems.www.authoring.cgi (if it's something to do with
           HTTP, HTML, or the CGI protocols). Questions that appear to be
           Perl questions but are really CGI ones that are posted to
           comp.lang.perl.misc may not be so well received.

           The useful FAQs and related documents are:

               CGI FAQ
                   http://www.webthing.com/tutorials/cgifaq.html

               Web FAQ
                   http://www.boutell.com/faq/

               WWW Security FAQ
                   http://www.w3.org/Security/Faq/

               HTTP Spec
                   http://www.w3.org/pub/WWW/Protocols/HTTP/

               HTML Spec
                   http://www.w3.org/TR/REC-html40/
                   http://www.w3.org/pub/WWW/MarkUp/

               CGI Spec
                   http://www.w3.org/CGI/

               CGI Security FAQ
                   http://www.go2net.com/people/paulp/cgi-security/safe-cgi.txt

This should be the first response to every question dealing with perl and error 500. The 2nd response should be "where's the sourcecode?"