Same issue here. I have a client who is getting a "Disk Error" when the USB cable is plugged into her HP Desktop. What we can narrow down, is it is not a bios update error, it lies with the printer. Their media access slots on the printer itself are being read as bootable devices (check the drives populated and registered in your bios setup... "USB Drive 0.0" wil be listed).
So, figuring out if there is a firmware update for that brother printer, or finding out a way to disable those media access slots until you are ready to use them... I dont have any other ideas.