In the fight against Arrok I charmed him, so that he fought for me. After killing all elementals the fight finished, the cutscene started. But after the scene, Arrok was still standing there alive, couldn't control him anylonger, but he wasn't hostile. I left the volcano, outside the volcano Arrok again stand there, not hostile, but couldn't control him. Then two game crashing options happen:
1) When I try to attack Arrok, the UI vanishes. My charcacters don't attack, I can only let them walk somewhere. Cannot do anything more, even the control panel over ESC does not open. Have to crash the whole game over the desktop.
2) When I ignore Arrok and go back to the map, I can choose the next aim and my group goes on. But when a sudden fight appears (all times I tried my group was surprised, and Arrok's portrait also appears there), I can click on the "start fight" button, but then the screen stays black. I can hear nature noises (bird tweeting, air etc.), but the screen stays black and I again have to crash the whole game over the desktop.