New "MAC-ID" ?
 

Had to replace my defective motherboard with an onboard ethernet card.....replaced it with same model motherboard but since it is a different ethernet card than I registered with I think that my "MAC-ID" (whatever that is?) has changed and that is why I'm getting th "Error #1" message when I try to run the program....Ican intall it...have the right id #...but can't run it

Someone please let me know if by changing motherboards with onboard ethernet cards I changed my "MAC-ID"? And if so How do we fix this?:f

Yes You Did
 

A MAC address is a unique serial number (of sorts) for ethernet Cards. The intention of assigning a unique address to every card is to aid in identifying computers on networks and the internet. If Two Identical MAC's existed on a network, they wouldn't work.

By changing your Motherboard with an on-board Ethernet port, you changed the MAC address.

You will have to request that MTU generate a new serial number for the new MAC address. I had the same problem, called them and they assisted me.