I am trying to set up WDS between my two AirPort Extremes. They are the white dome shaped ones. One is connected to my cable modem, but it doesn't quite reach my office. In my office, I have a 20" iMac G4 and my mid-2011 13" MacBook Air. Every time that I try to set up WDS, AirPort Utility says "There was an error setting up this AirPort device for WDS. Quit Airport Utility and try again." Any and all help is very welcome!