Did you ever get this working? I have about 30 cameras that are non Samsung branded (Dynacolor, Hunt Electronic) and none of them will register with the NVR, I also get the Connection Failed - Unknown Reason error code.  
  
Cameras: 10.1.128.X 
NVR: 10.1.128.2 
        192.168.2.2 
  
I can access the web console of any of the cameras when I get on the camera subnet, and the NVR can add Samsung branded cameras using the Samsung protocol, but any device trying to use OnVIF fails for unknown reason. I have the time of the NVR and cameras synced. Any idaes?