One main 802.11g & one expander. Used to work; can't get it set up again.

Question

We have two AirPort Extremes (both 802.11g)--the "office" one is connected via Ethernet cable to our ADSL modem. The "living room" one is at the opposite side of the house, and has worked for three years as a range extender. We had to change our WEP key today (problems with Windows machines), and once we did that, "living room" disappeared. We did a factory re-set of "living room," and it showed up under the Wireless Networks menu as "Base Station $idenfication" (having lost its name in the re-set).
I opened AirPort Utility, which showed both "office" and "Base Station $idenfication," but "office" had the green button to the left, while "Base Station $idenfication" had the yellow button. So I needed to reconnect "Base Station $idenfication" to "office"'s wireless network in order for it to work as a range expander, right?
I went into the AirPort Utility and chose "Base Station $idenfication." I was asked if I wanted to switch networks (I'm assuming from the regular old house network to this "network" the re-set base station has created), and I did. I chose "Manual Setup," and then "assist me." I named the AirPort, created and verified a password, hit "continue," and chose "Extend the range of my AirPort Extreme network." It asked me to choose the network I want to extend, which I did. It asked me to select the wireless device I want to join, and I selected it. It said "Configuring main network for a new WDS" with a blue progress bar.
Then it beeped and said "There was an error setting up this Apple wireless device for WDS. Quit AirPort Utility and try again.
So I did. And got the same result. Still with "office" with a green button and "Base Station $idenfication" with a yellow button.
Help?

Answer 1

To facilitate the WDS set up, try the following:
o Perform a "factory default" reset on all of the AirPort base stations to be used in the WDS.
o Place the base stations within near proximity of each other during the set up phase, and then, relocate them to their desired locations when complete.
o To avoid having to "switch" wireless networks during the WDS setup, attach each of the remote/relay base stations, via an Ethernet cable, to the main base station. Of course, this would be dependent on the AirPort types used.
o Be sure to jot down the MAC address for each of the base stations to be used in the WDS as these will be required during the setup.
o When enabling wireless encryption, configure the relay/remote base stations first and the main base station last.