Dinput.dll is a file use for "Mouse Freedom", a feature that lets you go out of the RO window in windowed mode.

To fix this issue :

  • Try downloading the most recent version of Mouse Freedom in the Downloads section and placinf it in /Gravity/RO/
  • If all fails, delete the file DINPUT.dll in Gravity/RO/ as it is only aa plugin and is not needed to play the game.