I've tried to upgrade to the new unstable OpenNI version (184.108.40.206). The installation was okay (had to restart because OpenNI didn't find an environment variable, but then it worked).
Everything seemed to run when I started the sample project from Visual Studio. But when I executed the compiled CCT.NUI.Samples.exe I only got an exception (nullreference exception because the pointer to the depth data is IntPtr.Zero). When I catched the exception the result was only noise:
I don't know why this happend but I guessed it might have something to do with the fact that I've got a 64bit machine but installed the 32bit version (this used to work with the stable version when I set the build output to x86).
After installing the 64bit version everything seems to work now. I've commited this version to CodePlex. The published binary will now also be compiled to run on 64bit.
To upgrade OpenNI follow the instructions given here: Avin KinectSensor
Download [Source] or [Binary]