I don't like that you're running a Win7 VM with so little RAM and VRAM: you seem to be aware of this, since you seem to have tuned the RAM allocation to an unusual (small) number. If possible you should shut down some host apps to free up more host ram, to give Win7 at least 1GB RAM, and 32MB VRAM.
If that doesn't help then I'm afraid you'll just have to wait for the next 4.3.x maintenance release that Frank mentioned.