I suspect it is locking up as I think there is a cut scene where you talk to the virtual born again virgin hottie Sassan.
Is Sassan in the room with you as she should be there and you both fight. Well she must be there as she summons him so that is a dumb question.

Anyways after he runs away Sassan should again talk to you about having to face the guy that killed her and getting revenge and that is where your problem is happening. That part of the game/cut-scene vid is corrupt or something.
Maybe try a little further back save game if you been saving separately as well as quick saving.
Or copying your Divinity 2 folder out of your C:/users/"name"/AppData/local? folder (Vista and Win 7 location) to some place just to be safe and reinstalling the game.


Windows 7 pro 64 bit
EVGA X58 motherboard
6GB of OCZ DDR3 memory
watercoooled i7 920 @ 3.8GHz (4+4 cores)
EVGA (Nvidia) GTX 275 graphics
Creative X-fi elite pro sound card.