Hmm... just a little update:
Is it possible that this guide http://forum.insanelymac.com/index.php?showtopic=69345&st=0&p=492434&#entry4924 34
for installing QI / CE.

I think that whatever it did to my sound driver it also did to my mouse driver. Before the installation My mouse4 button was recognizable, now it's just mouse1, and mouse3 doesn't work anymore.

Any ideas?