Greetings,
Aside from reiterating the previous suggestion regarding use strict; I think this is more of a configuration issue than it is a Perl one. Your error File download, some files can harm your computer... Sounds like you are using IE as your browser, and it doesn't trust your localhost; you may need to add it to your list of trusted sites. I forget how to do that since I only use FireFox these days, speaking of which have you tried this in multiple browsers yet (IE, FireFox, Galeon, Konqueror, Lynx_{yeah I said it} , etc)? I would try a google search of your error text and see what comes up. It is either that or your web server is not configured to run cgi scripts through Perl.

-InjunJoel