I assume you have the latest NVidia drivers for your graphics card, if not that's definitely worth trying.
In the 'bin' folder of the game there is a file called 'PhysXLoader.dll'. Is this correct? If so, try renaming it to 'PhysXLoader.bak'. Not sure it will help, but worth a shot.
The folder I'm talking about can be found at:
C:\Program Files (x86)\Steam\steamapps\common\divinity ii - dragon knight saga\bin