deleting erroneous network

Can you tell me how to do this?
Thanks

Thanks for the link to Apple's support document. As it turns out, I ultimately figured it out on my own. When I'd first tried resetting the AX, it hadn't taken out all the network settings; so I thought I must be missing some additional steps. I finally did get there, though, once I realized I needed the latest AX utility. I hadn't updated to the latest Airport Utility and that's what was necessary to accommodate both the "g" and the "n" protocols. The best news is, I'm now able to use DirectTV's On Demand and it's working really well. It wasn't completely easy getting there, though. In installing a new AX/n, there is the added option to "join a wireless network," in contrast to the already-existing option to "participate in a "WDS" network. I'd set up my "g" network as a WDS and initially tried to add my new AX/n to the WDS network. I never actually tested the DVR connection to see if it would work this way, but I've since read that it's best (for streaming, DVR connection, etc.) to use the "join a wireless network option" when using the latest AX for these purposes. If you did not opt to "join existing wireless network" when merging your two networks, perhaps this is your problem. I definitely think the AX should be able to support both the Ethernet and optical ports at the same time; one really has nothing to do with the other. In fact, one of Apple's suggested setups shows an Ethernet printer connection and an optical receiver connection in the same configuration. The Ethernet connection to your DVR shouldn't make a difference.

Another thing to note: DirectTV's instructions indicate that if your connection is set up properly, you'll see a "congratulations" when you go to DTV's Network Settings page. I did not find this to be the case. In DTV's Setup Menu, I got the option to "test" the network settings. When I selected it, it took me to yet another option to run a system test and it was only when I did this that it said the network was connected. The proof, however, was being able to bring up a complete list of all the available On Demand programs and actually see it in action downloading a program. Let me know if you're able to get everything working. Good luck!
Phyllis

My On Demand hookup is all connected and things are working very well with my "g" protocol network. The airport express connected to my DTV HR-21 is capable of running an "n" protocol network; but my network is only a g network, so that's the fastest it will run. The "g" protocol does slow things down significantly, though. An HD movie, running-time of 1 hour 40 minutes, took approximately 10-11 hours to download, depending on whether there was other network activity going on. Once the download was completed, however, I watched the movie and the picture was phenomenal--not one glitch or interruption in the playback and a really beautiful picture! So long as you're not concerned with having the On Demand more immediately, this works great!