I think you guys misunderstood me a little. I can't post any errormessage, because as soon as I compile the programm and it reaches this lines in code, my graphicdriver completly shuts down. Then it restarts with a message similar to: "Your graphicdriver has been restarted after a fatal error". I dont get any further information about it, it is NOT a compiler error, the code compiles fine.

I'll try NightCreatures suggestion as soon as I'm back home.
Checking the HRESULT of CreateBuffer (and everything else) gives just S_OK.

Even if your graphics driver crashes this shouldn't clear your debuggers output window, so the runtime message should still be available. Also make sure that the size of the data you pass into the buffer is the same as the size specified in the bufferdescriptor, I had this crash on me in a drawcall(callstack indicated a problem in the driver) when the sizes didn't match