Crashes at least once an hour in TSW beta weekend related to "A request to disable the Desktop Window Manager was made by process (4)"

I keep crashing in TSW beta weekend. Event viewer says "A request to disable the Desktop Window Manager was made by process (4)" is the first thing in the chain and then TSW crashes. It looks like the nvidia driver (have latest) is blowing up or something. Googling this error shows other games with the problem. Tried disabling 2nd monitor, turning off desktop composition for TSW, closing anything flash-related (browsers), no deal. Anyone know anything?

edit: sometimes I can tab back into the process and it says "the video driver has crashed, setting settings to low"