Xcode 4.1 GM Not Installing (must quit iTunes) on Lion?

I am trying to install Xcode 4.1 GM on my Lion mac but it's not working. When it is almost finished, I get the popup to quit iTunes even though it is already quit. So the only option I have is to quit iTunes helper or alert in activity monitor, then it finishes the install. However then Xcode crashes on launch. Any ideas?