Airport Express constantly can not stream music from any device My older Airport Express (b/g) was cutting off from being seen in iTunes and generally not performing well as a music server or a print server.

Purchased a new Express and still one or some of the computers will see it for an hour or so and then it goes away.

99% of the time I can not see it in Airport Utility when I am 5 feet from it.

Network setup:

EnGenius ESR-9752 with latest    firmware is the main AP.  This has    wired and wireless connections. 

Both    Airports have static IPs and are on    the same subnet and all set to the    same channel (1) as the ESR-9752.  I    can see them all from the ESR-9752.    APXn (Maddie) has the latest    firmware, Airtunes turned on and is    connected to my new speakers.

I know Maddie is working, because I am also using the ethernet port to connect our BlueRay player to the internet through it's connection.
Maddie this morning was playing music.

I can not see Maddie from the Airport Utility or when I try to connect using her MAC.

APXb/g (Xena) is sitting in a room 45 feet away pretending to extend the network (bruno) but I think she just sits there with a green light to make me feel better.

We no not have any cordless phones in the apt.  We are a cell phone only apt.

My computer will sometimes see Maddie and play.  None of the others, nor will our iPhones see Maddie.

I accepted the fact that my 5 year old APX may be going and shelled out for a new one - but that does not seem to be the trick.

With 2 AP Expresses here - how can I reliably stream the music from iTunes on all of our devices to at least one of them?
I've seen that on a couple of them, and the problem seems to be tied to IPv6 support. Mine would drop connections randomly, sometimes requiring a reboot of the AirPort Express before it would return to the network.

Turning off IPv6 entirely in the Network Control panel of our Macs seems to have fixed it. I can stream music to it for hours now without problems, so give that a try.