I am aware of database error messages a few minutes ago. I am checking what the cause was, but I think it was the hosting company doing the full site and backup I asked for a few days ago (so I can investigate upgrading to vBulletin v3.8.0).
I have confirmed that the cause was the backup I requested. It has to stop access to the database server while backing it up (which takes about 2 minutes), and that causes the errors.