not much I'm afraid - there's always the old stand-by: Utilities > Disk Utility : Repair Permissions.
You could also try moving the iTunes Library file to the desktop to see if it's that that's the problem rather than iTunes itself.
And if you can be arsed, try making a new account, log on to it, and see if iTunes opens from there (that will test whether it's a user set up issue, or a deeper system wide problem)