From what I can see at your error you created a seperate database, or have a prefix.
1. If you have a seperate database you need to put the ts monitoring script in the same database as vBulletin.
2. If you have a prefix you need to change the query to
UPDATE
prefix_user SET tsserver_timestamp='' where (tsserver_timestamp + 900) < '1114633609'
I hope this is the solution to your problems