I just removed firefox 3 beta and installed firefox-2, but after I did that (and removed my entire .mozilla folder from 3 beta before installing firefox-2), I lost the ability to use my mouse buttons for navigation!

It was working great in 3, my side buttons would go back and forward, but now they don't. Any suggestions? That's the only change that happened (i.e. no random reconfiguring of x.org or anything in between)