Can't disconnect from PC

Hey all. I borrowed a friends P2000, and downloaded some photos from it onto my PC.
However, now that I've finished, and I want to disconnect it I do the whole 'Safely Remove Hardware'thing, but get an error message 'The device 'Generic' cannot be stopped right now. Try stopping the device again later.'

Also, the PS2000 has a message on it 'Connecting to PC. Do not turn off power or disconnect the USB before the operation is complete.'

Any help would be welcome. If I just disconnect, will I lose all his photos??

Thanks