Make sure that you plug the printer in while the thin client is turned off. After plugging it in boot up the thin client. Log in and go to install a printer like normal. You should see a printer port named LPT2, this is the one that you want to select since it is what was mapped to that USB port. If you plugged in the printer while the thin client was turned on you have to turn it off and switch the printer to another USB port.