We just noticed that same "bayes db version 0" error as well. I was hoping someone already had an answer so I wouldn't have to research this.
It could just be a corrupted bayes database that needs to be rebuilt.
I also noticed that the required level for spam is now 6.6 (which lets a lot more through). I wonder if it's related.
I'll run some commands in debug and see if I see similar results.