How do I install Divx?

Okay, so I've tried installing divX about a thousand times, and each time it's says it's installed, but upon my trying to watch a movie with that requires divx, nothing happens.
Why is it that nothing's happening? I've followed the instructions of the installation precisely, and it even shows up as an application both in my finder and under the application tab, what I don't understand is why it's not applying to the internet.
Any suggestions?

CosmoPod
Is a Safari add-on that helps you download and convert Flash, DivX, WMV and Real Media videos from the Internet to your Mac / iPod / iPhone / AppleTV automatically.

http://www.cocoamug.com/cosmopod/index.html