Why does my CGI/Perl script fail with an error 500 (Internal Server Error)?

These errors are nearly always related to a coding error within the script, or bad variables being passed into the script. If you encounter an error “500 Internal Server Error” whilst running your CGI and Perl scripts, try the following in order:

– Ensure you have uploaded the script through FTP using ASCII mode (not Binary), or that it has Unix-style carriage returns.

– Check the interpreter path on the first line of the script. For Perl it should always be “#!/usr/bin/perl”.

– Make sure the script filename ends in either “.pl” or “.cgi”.

– Make sure the script can execute. It should have permissions of “755”. Most FTP clients support this.

– Put “use CGI::Carp qw(fatalsToBrowser);” into the second line of your script. This will make Perl print the error instead of the “500 Internal Server Error” page, and will allow you to find out where your script is breaking.

Other potential problems include bad syntax in an .htaccess file (if you’ve created/edited one). Check your error log for details (there are articles on how to get to your error logs).