Greetings all,
This may be a silly question, but have you checked the permission on the file you are attempting to execute. Also you may need to adjust the owner.group ownership definitions if you are running on Linux.
Your file must be executable in order to run (chmod 755 if needed).
Also your web server (Hopefully Apache) must be configured to execute CGI scripts.
Though these may be obvious questions to some, they are not implicitly obvious to all.
Hope that helps
-injunjoel
Another quick note: The text file may also need permissions tweaked. This can be deceptive when run from the command line -- you're running the script as your primary user, but the Apache (or whatever your webserver is) may run as user 'nobody' or 'www'.