Trying to play online

I want to play online against actual people. I tried to do the Voobly thing but it keeps saying I need to download a patch. I download the patch, but it still says I am missing it when trying to get on Voobly. I don't have the CD of the game. I purchased it from Steam.

When I do the download it first says "no CD found" or something like that, but then keeps going through the download, so I don't know if that has anything to do with it.