An error occurred while updating the configuration airport express
Air Port Utility shows a graphical overview of your Wi-Fi network and any base stations connected to it.
The primary base station (Home, in this example) is connected to the Internet via your modem or router.
One more thing - there seems to be a hint or two of problems with Airport Extreme 802.11n's latest firmware.
For instance, see This might find more love if moved to the Networking thread ...
I ended up choosing to go with the Billion 7404VGP-M, and I've upgraded that to the latest firmware (5.54b). I'm running an Airport Express over the same network that the Billion is on, but only to stream music to my sound system. Please make sure your Apple wireless device is plugged in and in range of your computer or connected via Ethernet and try again.
The Default Settings doesn't seem to be an issue as I'm about to change settings.
So I tick to ignore these, and 'status' then shows normal with a green light. I select the the Wireless tab, and for Wireless Mode I select 'Extend a wireless network'.
You may need to select your network from the Airport menu and try again".
If only Apple would introduce a Vo IP-enabled ADSL2 Time Capsule, I'd be laughing!!