NO HMD AND SENSOR DETECTED - DllNotFoundException

I´ve got a really annoying problem in Unity3d. When i try to start a project i get a black screen with NO HMD AND SENSOR DETECTED. The Oculus DK2 is plugged in and works perfect. Copy the DLL in the Editor folder didn´t work for me :cry: I´ve uninstalled the whole Unity Software and all DK2 Software parts. After that i downgraded my MS Visual C++ 2012 x64 to a lower MS Visual C++ 2010 x64 Version. Then i installed the DK2 Software Parts (runtime) again an configured it. I´ve installed the Unity Software, downloaded the SDK for Windows again and extracted it into a seperate folder. I downloaded and extracted the OVR Unity 0.4.2 too. After loading the package in Unity and disable the DX11 support in the Project Settings i try to run a project with the OVRPlayer Prefabs and get the scene fading in and suddenly the screen went black "No HMD and Sensor detected. The DK2 is plugged into my USB 2.0 Ports and the video signal over HDMI. The DK2 is set to Extended Desktop to the HMD. I can start Demos like Don´t Let go or Ocean Rift without any problems. The tuscany demo works perfekt. I´ve got a Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz (4 CPUs), ~3.4GHz and 16384MB RAM - NVIDIA GeForce GTX 670 4028MB -Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1.

Oculus Runtime and SDK 0.42

Error message in Unity:

DllNotFoundException: OculusPlugin
OVRGamepadController.GPC_GetButton (Int32 button) (at Assets/OVR/Scripts/OVRGamepadController.cs:117)
OVRMainMenu.ShowLevels () (at Assets/OVR/Scripts/OVRMainMenu.cs:759)
OVRMainMenu.UpdateSelectCurrentLevel () (at Assets/OVR/Scripts/OVRMainMenu.cs:730)
OVRMainMenu.Update () (at Assets/OVR/Scripts/OVRMainMenu.cs:355)

Please help me.