Thank you for your suggestion Tesserax. I followed the same instructions and got the same results. Configuration succeds, light is green. Airport has access to my wireless airport but iTunes can't find the speakers.
I won't be able to check this issue for a few days but thank you once again.
I have struggled with the same issue. I have a Dlink attached by cable to my modem. My AE is connected to my powered speakers so that I can play music from my ipad/iphone and I set it up to join my existing (dlink) network. It only works for about 2 minutes and then it'd one. AE is not recognized. So I phoned Apple and they said "oh, no, AE only likes Apple products and won't work with non-Apple" if I want to send music to my powered speakers I need hard reset my AE, set up a new network on airport utility for the AE and then when I want to send music from my iphone/ipad to the speakers I need to disconnect from my wireless network on my iphone, connect to the AE network and send music that way.