Suddenly iTunes on my computer is having problems figuring out if it is authorized on my computer. Every time I try to authorize or deauthorize my iTunes account, I get a message bubble like in the screenshot I'm attaching. I've tried repairing permissions with the Disk Utility, but I still get it. Does anybody have any idea of what is going on and how to fix it? Incidentally, this computer has worked with my iTunes account since I got it a year ago. When I sync my iPod, it says that the computer is not authorized. Thanks!