I assume it's not this side (forums.cnet.com) but some other site that you call "this site".

So it doesn't work in Firefox on your PC. Alas, the only one that can answer your question "Is it the site or my browser that has the problem?" is you. It could even be your PC.

To answer your question:
1. Try it on your PC in another browser: IE, Chrome. Works? Then it was the browser.
2. Try it on another PC (friend, family, work, school, etc). Works? Then it was your PC.
3. Works nowhere? Then it's the site.

Simple recipe to get the answer to your question.