This being a generic error, it could be caused by many things. Here are some of the most common:
1) Your script is not CHMOD 755. (you can do this with your FTP program. Any script you try to run that isn't chmod 755 will result in an internal server error.
2) You have incorrectly set the path to Perl in your script. It should be /usr/bin/perl
3) You uploaded your script in 'binary' mode on your FTP program. Retry, setting your FTP client to 'ASCII' instead of binary.
4) You have used invalid Perl arguments
While we can't possibly troubleshoot scripts for everyone, if you are having serious problems and have read the instructions for your program, AND tried the above, then please open a trouble ticket and we will help you as best we can. We don't normally do script installation, but we don't like to leave our customers out in the cold either.