Database error in vBulletin :

Cannot use database 34227_theatreconsultantsorg

MySQL Error : Access denied for user '34227_user124210'@'%' to database '34227_databasename'
Error Number : 1044
Request Date : Tuesday, July 6th 2010 @ 05:31:27 PM
Error Date : Tuesday, July 6th 2010 @ 05:31:27 PM
Script : http://www.domainname.org/forum/register.php?do=signup
Referrer : http://www.domainname.org/forum/register.php?do=signup
IP Address : stated IP address
Username :
Classname : vB_Database
MySQL Version :

What would make it just stop working? When I go to the log-on page it says:

Database error The database has encountered a problem.

I just changed the license URL address on vBulletin Board, but can they go into a site and take the bulletin board down without passwords? I have no idea how to go back in and start fixing it. I do have it all backed up of course. But I cannot even sign on to get into the admin panel. It is 3.8.4.

Thanks so much for your help!
Cheers,
Janell