Airport Extreme & Airport Express Networking


Although I believe I am very proficient with Macs, networking remains a mystery to me. I am using an iMac G5 (20") with OSX 10.4.2 and an Airport Extreme card. My internet access is SBC-Yahoo DSL. What I am trying to do is set up a small home network using 1 Airport Extreme base station and at least 2 Airport Express units to (i) access the internet wirelessly with the dsl modem plugged into the base station (iMac is 6 horizontal feet from base station); (ii) print wirelessly via two USB HP printers plugged into one of the Express units (about 12 horizontal feet away from the base station); and (iii) use the "Airtunes" feature to play music from my iMac to my stereo, approximately 25 vertical feet away, using one of the Express units.

So far, hooking up the base station to my DSL modem and getting on the internet wirelessly was a snap--I didn't do anything, and it worked. But everything else won't work. Both Express units are flashing amber. I tried to use the Airport Setup Assistant. While it located the base station and both express units, I get a message stating "There was an error communicating with the base station." (On my first attempt, I got a message stating "Airport Setup Assistant cannot communicate with this base station.") When I try to "configure" the Express units, I get a message that the utility will have to "change the wireless settings." When I allow this to happen, nothing changes. I also tried the Airport Admin utility, which recognized the base station but cannot seem to configure it (I get the beach ball). I also tried resetting the Express units, but nothing changed. I further tried using the Printer Utility, but it did not recognize my printers.

I have not made any other changes in settings. I would appreciate any other advice/assistance that you can provide.