You can try and run PhysX from the redist folder in the ArcaniA game folder.
1. Open C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common 2. Copy cudart32_XX_XX.dll AND cudart64_XX_XX (XX_XX I'm guessing are a reference to the version. Mine were 41_22) 3. Paste to files right into the Game file Steam\SteamApps\common\Arcania Gothic 4 (No Subfolder)
Originally found by Righteousnuts to my knowledge.