I just had the same problem, coincidentally when I was trying to load the game to demonstrate another bug

Here's my dxdiag.txt and debug.err, hope that helps!

I had a saved game that showed a very odd movement (I tried to move my sovereign to a quest hut; he moved there, but then moved on his own back to one tile from where he had started), but was able to load the saved game only once to confirm that it reproduced the bug.  After that, no matter how many times I tried, I was unable to load it to use Jing to record the strange movement.