I just upgraded my iTunes to 184.108.40.206 and after tried to sync my iPhone with Yahoo Address Book and it failed. No other problems, just Yahoo Address Book. Not sure it has anything to do with the upgrade but I have "never" had a problem before with this. I have tried a number of times with no luck. ".... unknown error occured (4). Please try again later." Anybody else using Yahoo Address Book with iPhone Contacts?