Using the AC adapter for the Mbox 2 Pro on a desktop computer can cause these errors. There are only two times the AC adapter should be used:
1) When connecting to a laptop computer.
2) When connecting to an iLink 6-to-4 pin FireWire cable (most common in laptops).
Unplugging the AC adapter and letting the Mbox receive power from the FireWire bus can resolve these errors.