Currently I am using Windows Vista and using Microsoft Visual Studio C++ 2008. I wrote a program using the DirectX March 2008 SDK to test out the cartoon shader I learned and I get this error:

"error x3025: global variables are implicitly constant, enable compatability mode to allow modification"

I looked up on the compatability mode and tried it out on the visual studio .exe and still no go. Has anyone else received this error and is there a known solution? Any help will be appreciated.

Assuming the error is raised by fxc compatibility mode means the /Gec command line option (or the D3DXSHADER_ENABLE_BACKWARDS_COMPATIBILITY flag for the D3DXAssembleShader* functions), not Windows compatibility mode. The error indicates that you are modifying one or more global variables, which is not supported by the HLSL compiler anymore.