@Pondini: did you ever get to the bottom of the cause why BackToMyMac can cause this problem? Is there a clue there? I've signed this machine out of what is anyway now a defunct MobileMe account (as it's a Leopard machine it can't access iCloud)
I don't think it was fixed in Leopard, but seems to be ok in Snow Leopard and Lion. I haven't seen a post about it in a long time.
However, if turning it off didn't help you, the problem must be elsewhere. As BDAqua says, there appear to be deeper problems on your system.