Try disabling the DWM (Destop Window Manager Service) I hear that some people crash with it on (i personally do not mine LTC)
However the error Clearly states that its Allegedly your video drivers crashing/overloading/restarting/rebooting, Have you tried reducing the inensity? Try some default settings or a lower overclock (LTC uses memclock)
i reduced intensity to 10 but still had same issue. I am at loss about this...