Well I guess the plot thickens. Yesterday, I connected the CM15A to the outlet it's usually plugged into with an extension cord as I've done before. I verified that the unit is plugged in the receptacle with neutral wire intact (in other words to be sure I wasn't inverting the device in the socket). This time the module that's been the problem did not turn on from the PC as before. I tried to unplug everything on that breaker to be sure there wasn't any interference and no change. I could however control another wall receptacle in the same room 100%. Always on and off as instructed by the PC. No dimming, but that's OK. So, I decided to make that lamp my scheduled device. I deleted the programming on the previous lamp (a wall switch) and programmed the lamp (a wall receptacle) with the commands to turn on at dusk. All other lamps programmed to turn on at dusk did, but that one did not! What the...?