Site Suspended mySql calls overloading server?

[DarknessDivine]

How is this possible?
I have a friend who is using vBulletin, today his account gets suspended and this is what they tell him:

Your mysql calls were overloading the server. I will forward you to our Suspended Accounts department for more information.

The only thing he has running is vBulletin, no portals or anything.
What could be causing this?

[Steve Machol]

Not enough info to really do anything. Perhaps his forums are simply to busy for that server and host.