Just found this thread, what a pity, I could have saved myself a lot of trouble.
Had the same problem, never suspected MBAM as I have been using it many years. Eventually found it was causing the problem after elimination using MSCONFIG. I uninstalled and used the clean utility, but when I reloaded and used paste and copy of the serial and id numbers, it said there was a problem with the activation and to contact support. As it was Christmas I went back to an earlier image of Windows 7, a lot of hassle, and it is now running fine with MBAM disabled. Just hope they fix it soon, but I will want to be sure before I run it again, as it was supposed to be fixed in the last patch 19th December I think..