I have never used an Airport Express before and am having trouble getting started. I plugged the Airport Express into the electrical socket and started the Airport Express Setup Assistant. Right off the bat, the Assistant software gave me a warning that no "wireless interface" was detected. I'm not sure what this means, as I have a wireless network set up (using a Zyxel router/modem). Any ideas on what to do? Thanks in advance for any help you can provide.