Hello, I've got a 16GB 3GS running iOS 4.0 and all of a sudden today the phone refuses to back up. iTunes is giving me the error "iTunes cannot back up the iphone because an error occurred." It continues to sync after that and move apps and music around, but it won't back up. I tried again after that and it wouldn't sync calendars, contacts, notes, etc. Whats going on here? By the way this is on a Macbook with the newest updates for Snow Leapord and iTunes.