Hi,
First of all, do you have Microsoft Kinect SDK installed? if you do avin2 drivers wont be called and you will not be able to see the camera.
If you dont have them installed, have you tested the sample (NiViewer) that got installed with OpenNI?
If that is working, last resort: uninstall the libraries and install the 32 bit versions of each (in this case you will probably have to copy OpenNi.dll inside C:/Program Files (x86)/OpenNI to LKB directory) .
Let us know if it worked
Good luck!