I'm not getting a 404, I'm getting a 405 Method (POST) Not Allowed. If I GET it, I see the source code. It's definitely a web server configuration issue. The most likely causes are: the web server wasn't configured to run CGI scripts from that directory, or the permission aren't set right.

You should use strict to avoid coding errors. You should use CGI instead of writting your own CGI parser to make sure you're doing things right. You also have a security flaw allowing the script to be used to send emails to anyone the user desirers since you accept the recipient from the user. Might I suggest you use the NMS's FormMail instead of writting your own script?