Why can't I change the movement controls from WASD to Arrow keys? It says arrow keys is already being used?
If you can't figure out how to fix this and are willing to use an alternative, try autohotkey with this script:
Up::W
Left::A
Down::S
Right::D
Just make sure you shut it off otherwise you can't use the arrow keys for anything. There's a feature in ahk that checks which window is active but I don't have the game so I don't know what it runs under.