Is there any indication in the vmnware.log file what thread ID 50961 is in this particular instance? That might lead a clue what is crashing (e.g. virtual video, virtual disk, etc).
Considering that the host system is a laptop, does the crashing happen ever when the laptop is plugged in instead of running on battery power? Running on battery power could possibly lead to power saving situations and turning off host devices and essentially pulling the rug underneath the VM.
