Well if you can't recreate the userlist table for whatever reason.
1. Reinstall vBulletin.
2. Download the Impex system from vBulletin.com/members
3. Use impex to import all the readable data from your current database into the new one.
Instructions on how to install vBulletin and use Impex can be found at
http://vbulletin.com/docs they've got it explained the easiest.