Why did you do that? That's exactly why it's messed up. Pacifist isn't perfect.

My guess is that Iridium is using too much memory on your Mac, and so you should probably uninstall that (or at least just to make sure you can do it without coming up with "not enough memory" errors).

What I think you should do is delete iTunes.app, and then visit http://www.apple.com/itunes/download/ and download iTunes 7, and then install it using the included installer.