Thank you for your responses.
Here's a little more information. The steamer with ERR command, shows a lot of sparking from rollers under the tender. There are also two rollers under the engine that don't spark, and all four rollers are connected by one of the wires running through the connector plug between the engine and tender. All this started after having reminded it what it's ID code is. The ERR boards had been returned earlier to GRJ for checkout a few weeks ago because I was having trouble programming the engine. I believe the real problem at that time was a poorly seated radio board to the command board. I checked that to see that it is still seated.
The other engine problem involves the Lionel T&P F7 ABA where the lead engine has forgotten its ID. The F7B Bass unit seems to have remembered its ID. I haven't seen sparking from rollers on these engines. I have reprogrammed the A unit but haven't yet retried them as a train. I'll do that this afternoon.