After you re-connected the battery, did you re-set the clock?
It's been a long time so I can't really remember all that well, but in the old threads, I think someone mentioned unsyncing the phone as a possible fix. Generally, what it is, is that there is a CANBUS communication issue, and if you take it to a dealer, they can hook up the computer to proxy align to fix the problem. One thing I'm afraid, if you take it to a dealer, most of them are so fucking incompetent that they'd tell you that there's a bigger problem and try to sell you a new cluster or something, which rarely was the case with this issue. You may want to look through the old thread on this, also on the blue forum, too.
Edit - one more thing, make sure that your car has all the software updates done.