I've got an iMac and a MacBook and want to set up a network so I can use the MacBook to connect to the internet wirelessly, and share the printer. I bought Airport Extreme at the advice of the sales guy at the Apple store, who told me that's what I needed because my cable modem (OOL) and my iMac have only one ethernet port each. I was instructed to plug the airport extreme to the cable modem with ethemet cable, then the iMac to the airport extreme with ethernet cable.....Doesn't work. No internet access, the airport is flashing amber, the error message reported is that my wireless device doesn't have an IP address. I put everything back as it was so I could get back online...How do I get this working?