Sorry arbour, we do keep getting this, I noticed it today also.
Maybe I better not upload so many pics ...
Naw, joking aside, Ian may have a clue as to what it may be ... at least we ain't the only forum having a 'problem' as one of my other sites was doing the same.
I got an e-mail at 6:48 telling me the site was down, but the scripts rebooted the server and got it back online. I think deleting threads may cause problems, as I've had it go down once when I tried it.
I'll run a DB repair and see if that does the trick now.
I've spotted something that might have caused some problems, but I've implemented a very hodge podge fix on the server to stop it from happening until Microsoft release a patch (its for the same thing that caused problems a while back). Think duct tape and string-esq, but it works