After following these directions, Airport Extreme "cannot be found" and disappears from icon menu.

I followed the directions in the article. When I clicked "Update" in Airport Utility, after about 3 or 4 minutes I got a message saying that the network could not be found. It's icon had disappeared from the menu. My internet service was not available. I had to reset the base station and start over. The same thing keeps happening. Crumby instructions (non-existent in the manual) and no results. Any comments are welcome.