Dunge

Also note that the official SDK documentation/tutorials/samples are quite good too.

It's not a DirectX file format, especially since Microsoft already used it for that Office backup file you mentioned. Probably some custom file format made for the game. Open it with an hex editor maybe you'll be able to extract something and make a custom parser.

Just as future reference: This kind of situation is very easy to debug. When you get this exception, Visual Studio should break at the problematic line. This particular error message means an object is not instanced (null pointer), so you just check every object on the line by moving the mouse over and you will see that in this case either "Ground" or "Bones" will be null. Check when it was supposed to be loaded and here's your problem.

Go to nvidia control panel / catalyst control center / whatever equivalent for intel card and check the second monitor.