One thing that you must test before running a script via cron is, whether it runs from the command line.

Your script does not run via the command line, because the shell does not pass parameters like CGI does.

So I can only recommend to remove all the CGI crap, to take the script out of the document root, and to run it like a normal script. You might also need to make the script executable (with chmod) and check that perl is actually at /usr/bin/perl, as referenced by your #!-line.