I discovered this when upgrading, I thought I might pass it along, in case it happens to someone else....
The upgrade went fine, and I ran the update.php script to upgrade from 1.1. However I recieved 4 messages like:
ALTER TABLE cpg_comments add msg_raw_ip tinytext ALREADY DONE
Whenever I tried to view a picture, it gave be a critical database error.
I found that my database user didn't have ALTER TABLE permission.
If this happens you will need to run the 4 ALTER TABLE commands in the sql/update.sql file as a user with update permission.
Perhaps a permissions check should be added to the update script?