USB Problems using Parallels

Anytime I connect a USB device (printer and thumb drive is what I have tried so far) when I am in XP via Parallels I get an error from OS X saying something to the effect of "The USB device you are trying to connect is in use, try waiting 5-10 seconds and try reconnecting"

I am trying to add a printer (Dell A940 which I think is a copy of a Lexmark) and having all sorts of trouble.

Has anyone experienced this? What can I try to solve my problem? Thanks so much.

Eric