I am having this same issue. Did you find a solution to your problem? I am seeing this problem in OSX 10.8.2, only in Address Book application when sync'ing contacts to icloud. Error is:
[NSRangeException] -[__NSCFConstantString characterAtIndex:]: Range or index out of bounds
I would greatly appreciate anyone's help here. Thanks!
Just found the solution!! (if anyone still needs it)
Just go to icloud in your system preferences, log out and the log in again.
It will prompt you that everything will be erased from your computer.
If you have it on icloud, no problem; once you log in back, everything will return and...your contacts will be synched.
Let me know if it helps.