If you are using Vista, read the sticky for installing addons. Vista / WoW (not sure which) created a new folder for public games (or something.. I'm not a Vista user.)
If not using Vista, I'm clueless how to fix you up without the usual "are you sure you dowloaded the right (updated) version of the addon and installed it to the correct location?".
http://www.wowinterface.com/forums/s...ad.php?t=14762