The OS version could be it, I can't find any documentation though. I'm not really equipped to troubleshot so I was going to try to ask on the forum, but I didn't get my confirmation email when I tried to register and it's not letting me log in. If anyone who reads this has an account there maybe you could make a post or something.

Odd. I take it you double clicked on it to make the application install it for you? If so, could you check in '/Users/yourname/Library/Application Support/Adium 2.0/Sounds ' to see if it's there?

I don't have any other ideas than that. Apparently it seems to be working for some people since it's been reviewed. Oh, what version of Adium are you using? With vers .77 it works fine for me but maybe if you have an outdated version or beta they do sound differently?