I have owned Worms World Party for a while now, and it is only recently that I decided to play online. I tried downloading the patches at http://wwp.team17.com but none of them seem to work. The US patch made the computer ask for the WWP disk, even though it was in the drive, and the EU patch simply didnt work.

Check if your game isn't already patched.
Move your mouse cursor over the WWP logo on the main menu or check the properties of the wwp.exe in Windows.

But I assume that you got the message to patch your game for online play... :-/

Yes, when I tried to access wormnet it advised me to upgrade my version of Worms World Party.

I think the aussie version doesn't have a patch. Play WA instead. Or you could wait till the maker of the WA patches combines WA and WWP.

1. Uninstall wwp properly.
2. Install wwp.
3. Download the patch with the CD picture next to it that matches your CD picture.
4. Install patch.
5. Play.

3. Download the patch with the CD picture next to it that matches your CD picture.
Obviously there are a few versions of the game around that have a different CD image than those 3.
Sproing's Aussie version seems to be such one.