Since I upgraded to 9.1 this week, every time I try to sync my iPod iTunes pops up an error message telling me that it can't sync content from Audible b/c the computer isn't authorized for that account. If I click to play an audiobook, a login box appears, I type in my password, and everything is fine. I never had to do this before. Is anyone else experiencing this problem? Suggestions at an easy resolution?