Hi Roger,
I had a similar problem with one of the three I was changing the start channel on. After several attempts I programmed the pick again and then tried to set it but it still wouldn't program to the channel I wanted, after several tries and a few terse words I got it yah!!
I used the second option to set it;
OPTIONAL Way if the above doesn't work - From RJ
Step 1 - Start with the MR16.
Step 2 - Turn it on and using my address utility start it sending the address you want out.
Step 3 - With the MR16 still powered carefully move the jumper.
Step 4 - Count to 3 seconds.
Step 5 - pull the plug on the MR16.
Step 6 - put the jumper back to operate and power it back up.
I have edited this to avoid confusion.
Strange the others programmed without any problems but one was a real pain? All good now so the right lights are doing the right things :-) Good luck with yours.
Kev :-)