If you're getting any of these errors:
it's most likely that you uploaded the script in binary mode.
YOU MUST UPLOAD PERL SCRIPTS IN ASCII, NOT BINARY.
The script must have permissions set to be executable by everyone, readable by everyone, and writeable only by the owner - mode 755. You can set permissions via telnet ("chmod 755 script.cgi") or many FTP programs (in WS_FTP you can access the "chmod" function with a right-click).
Another easy way to set permissions on files and directories is by using your SiteMadeEasy Web Control Panel. Go to http://yourdomain.com/cgi-bin/plusmail and select Site Manager, then click on the icon next to the script you want to set permissions on and follow the prompts.
If, after checking permissions and uploading in ASCII you are still getting "Internal Server Error", try executing the script from telnet and seeing what error messages it produces.
Be sure you have the correct path to Perl.
There is also an extensive online manual available.
http://hostings.com 888-404-HOST (toll-free US/PR/VI/GU), 706-897-4743