The PhysX installer might give an error, but the demo will continue the installation regardless. If you don't have the PhysX Software on your PC, you can download it from the NVIDIA website at http://www.nvidia.com/object/physx-9.10.0513-driver.html
ArcaniA: Gothic 4 is set about 12 years after the events shown in Gothic 3, and again invites the player to a fantastic journey through a war-torn world. The ancient, nameless hero, who by now has been crowned King Robar the Third, commands a rigorous regiment over Myrtana and the Southern Islands. Luckily, not all subordinates live in fear and submission to the King and a new hero emerges, with the intention to settle an old score. The demo comprises the first two hours of the game and shows the beginning tutorial level on Feshyr Island featuring selected quests.