A problem that comes up a lot is the "usb device not recognized" one, where you can't access the reader on the computer. A simple soft reset solves the problem. People keep asking about that all the time.
Another problem with the prs-600 that stumps a few people: Sometimes it freezes. Not often, but when it does, again you will be fine with a reset. Only after resetting you also have to push the power button to restart the reader and renew the screen, otherwise it still seems frozen, because the screen hasn't changed.
If we all chime in with little problems we've managed to solve, I think we can make a good and helpful guide.