My kind of thinking and I hope they can help;)
Well I thought it had been nixed. I had been using for an IPv6 Tunnel and it had stopped working, so after trying all I could, I was not with BT then, and I just switched it off, unplugged it and left it.
Today 2013-06-22, I powered it back on, on my Mac the Airport Utility had fired up of its own accord, 2 messages about the Airport Extreme, a firmware upgrade was available and an IPv6 Tunnel error.
Did the Firmware upgrade AOK, so I'll probably just reset it to factory defaults and reconfigure it from fresh.
I have 2 Airport Expresses model A1088 i.e. the old 802.11g Fast Ethernet capable ones, so will probably have a play with one of them at a time, Any ideas re the problems reported in this thread I'll come back with them.
As DS said refer to http://bt.custhelp.com/app/answers/detail/a_id/44798/kw
Forget about BT tech support as it's a third party device i.e. APPLE's. BT's interest ends when you mention Apple Airport Express, the only advise they can offer is in the BT kb article above. So it's use Google and Apples kb articles
Next I would start with as hard a reset as you can do, see Apple's knowledge base start with
entitled "Resetting an AirPort Base Station or Time Capsule FAQ"
After many hours on the phone with the BT tech help centre (which is a pyable service) they were unable to resolve the issue. HERE IS THE FIX-1) buy a new aiport express (AE) and plug in to the BTHUB4 via etherenet cable in the wan port of the AE. Run Aiport utility and set up new AE. 2) Plug in old AE and rest it. 3) Aiport Utility picks up the old AE and add it to the network (no eternet cable required). Green light appears. Unplug and trasport old Aiport express to any room-plug in, wait a few mins and green light will appear. I have run my speakers through the old AE for 2 days and all great. BT AS USUAL WAS RUBBISH! THX BT FOR ZERO HELP.
Not as drastic a problem as some seem to suggest. Connect the AE using an ethernet cableto your computer - not the Home Hub. Start up AirPort Utility and go through the manual set up to create a wireless connection. All it's wanting really is to know the new wireless key. Hope this helps 🙂