Starting a campaign not possible

[Jostabeere]

Bought a hardcopy on Amazon, installed, patched. Tried to start the game. Clicked Singleplayer, clicked campaign. Nothing happens. Can't do anything. Load game button doesn't work, other buttons don't exist. Multiplayer and coop working fine. What do to make singleplayer work?

[Solais]

Can you post screenshots, also your log file? (located in Steam/steamapps/common/serious sam 3/logs/ ).