we had recently the same problem with the non displaying numbers on the cameras. I have found a solution for that.
First I have to say, that I think its due an "overload" on the USB bus or at least a wrong USB cable/hub setup.
You can check this with starting with just one single camera (license cam) and than add camera for camera.
To keep it short, our solution was to buy two additional hubs, our 12 cam system is connected over 4 hubs now and everything is fine again.
hope it helps
