Oxygen 25 Keyboard STOPS, all other cntrls OK

I have an M-Audio Oxygen 25 that works fine, but sometimes the keyboard on the Oxygen 25 just stops working, yet all the other controllers continue to work fine. Th only starts working again when I re-start the computer. I called M-audio and was told that the bandwidth of the USB was divided by how many devises I had in the Hub. I was advised to use a USB port on the Mac to keep the bandwith from being divided and that would solve the problem. The PROBLEM syill exists. Does anyone know about this? My other two controllers are not on USB.