USB Connectivity Problems

What could cause a problem with a PNP Digital Camera that the manufacturer says all it needs is the usbstor.inf driver installed (mass storage device)? The camera should start when plugged into USB (it doesn’t). Error message: unable to find a functional driver. Error codes: 28 and 10. I also have to turn the camera back on after uplugging the USB cable by removing and reinserting the batteries.