"Navigate to the install of COD:AW
There should be a folder caled Redist, or Preqreq.
Inside will be a DX, or a DirectX folder.
Run DXsetup, or DirectXsetup from this folder.
This should* solve your issue.
You should also verify the integrity of the game cache.
Right Click COD:AW in your STEAM library.
Select properties
Select Local Files Tab
Select Verify Integrity of Game Cache "