Was that while the upgrade was running perhaps? If not, that would indicate that the upgrade hasn't run 100% -- at least one step appears to have failed, though I'm not sure how that could really happen. Is it still happening?
It's still happening, 4 counts in total now, the last of which was 18 minutes ago. I did have a few difficulties with upgrading, but I seemed to get there eventually. Like you said, I don't see how one step could have failed when everything else worked.
Unfortunately restoring a backup isn't really an option. The problem is persisting, though:
Zend_Db_Statement_Mysqli_Exception: Mysqli statement execute error : Field 'ip_address_old' doesn't have a default value - library/Zend/Db/Statement/Mysqli.php:214
Generated By: Unknown Account
Excuse my limited database knowledge, but can I not simply assign the field a default value?