If you're seeing a shader error, it's probably your DirectX -- try one of these links:

https://www.microsoft.com/en-us/download/details.aspx?id=34429

https://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=35

If the game appears to be running slowly or dropping frames, try switching your monitor resolution to 1280x800!

:)