It does now work, now just trying to understand why and how it works the way it does.
Interestingly - I had two entries for the same machine:
A) local LAN address
B) WAN IP via port forwarding
When on the LAN, I could copy, control, view etc... everything worked. This was with a 192.168.xxx.yyy number.
When remote, I use the WAN number setting; configured (other than WAN address) the same as the LAN.
It would not do copy successfully. Came back with "Copy to this computer: failed on all"
Then after your posting, I noticed that the LAN entry had updated itself (seriously) from LAN address to WAN address, and was displaying both entries with WAN. However only one entry is "updated". Pic included.
As I build up the support network, just trying to understand the functionality of ARD etc.
For example, how did ARD "find" the LAN machine via the WAN (second entry??) and update the info, and allow copying, yet the original creaetd WAN entry won't copy???
Oh, and I will update your entry to note that you solved my question, soon, just hoping to get some additonal feedback without generating 100 extra post/questions!