scan doesn't find airport express / when it does, can't connect
I'm running 10.7 and using an older Airport Express, so I installed the 5.6 utility. It does not find my AE even when I do the hard reset and unplug it and plug it in again. Any other tricks for helping my iMac "find" the Airport Express.
—Update after I posted. Okay, it finally did identify the Airport Express, but--as has happened before--the process of having it join an existing Wi-Fi network ended with an error message: "The was a problem connecting to the existing Wi-Fi network. You may have to select the network again." (I'm paraphrasing.) Now the utility doesn't find the Airport Express when scanning again.
But assuming that it does find it, how to get the process to complete successfully?
iMac, Mac OS X (10.7), mid-2011 i5 iMac