Thank you all. I tried all the suggestions. I have unplugged the last light and won't use it again, at least during this testing.
I had to fool around with the on/off buttons to get the first transceiver to work on the same line as the plug in remotes; all seemed to work fine so I tried the second transceiver. The second transceiver was not quite on the correct house code, so I fixed that and all worked fine so I put the second receiver back in the original spot.
But now I am even more confused. Here is the scoop:
I had Lamp modules on code 1, 2 and 6; all on different outlets.
Codes 2, 4 and 5 were all on the same outlet - two lamps plugged into appliance modules and one chime.
For a few minutes, all worked, even with the battery remotes. But then, #1 Lamp module stopped responding even with the plug in remotes. So I switched it to an appliance module. That worked fine with all remotes. But then #2 Lamp would not react to #2 controls, but reacted fine to #1 and #6 signals!
I unplugged the transceiver overnight and will try more tests tomorrow.