Yes you have DirectX 10 as that comes prebuilt into Vista. But the issue is that you are running a DX9 game. While DX10 can emulate DX9 it does not do it well. So what you can do is install the DX9 Runtimes which will NOT overwrite your DX10 but work along side of it.
Therefor for whatever game you play be it a DX10 or DX9 game the appropiate DX will load and work perfectly with it. Which should help with the Vector Shader issue you have recieved. I think.
This is just a guess. As it could be something more or less complicated. I am just trying to help troubleshoot. Link ot DX9 Runtimes:
Download details: DirectX End-User Runtime