I can appreciate people are always moaning and groaning because your forum is part of a large community on our own Network. Our Users have been complaining that when they turn off the left or right column it makes everything centred within the forum. I have several different types of wrappers and I seem to get this problem everytime so there must be a Tag somewhere that isn't closed off. If you have a quick fix I'd be happy to hear about it.
Turn off the left column? OFF
Turn off the right column? OFF
And ya have you use a unique header/footer for this forum like we do.