1. The first image show light from faceted normals because each vertice's normal is only using the vertices on the same triangle.
2. I don't understand the second error but the .x model format was never made to be used outside of the DirectX SDK. "Tutorial07" in the DirectX SDK show an easier way to store model data in your own array for more speed, stability and control.
I recomend using bump mapping in the pixel shader so that you can get a higher detail level without any work on the CPU. Just sample the bump map multiple times with offsets to get smooth derivatives and use normalize(DX, 1, DY) as the current pixel's normal. The bump map can be reused as a displacement map for the vertex shader so that you can get dynamic detail adaptive GPU accelerated terrain. The bump/displacement map can then be modified on runtime when playing the game.