Cannot get Migration Assistant to work 10.8.5

Nearly frustrated to tears. Spent all day trying to get my brand new iMac going. Thought it was going to be easy... and it should be. Here are the details...

Going from an iMac from mid 2010 with 10.8.5 to the new iMac just released this week with 10.8.5. Using ethernet cable. Tried the old mac as a computer, and also tried in target mode. The differences are...

In target mode, the new computer never sees the old one. When NOT in target mode, the new computer DOES see the old one, but the old one never connects with the new one. The new computer gives me the confirmation number, but then says the other computer is not responding and I have no option but the cancel the transfer.

I turn the WiFi off while trying the transfer. No change.

Tried the Disk Utility on both computers. Both fine. No change.

The Engergy Saver is set to "Never" on both computers.

I'm traveling, so I do not have the disks for the old computer. Reinstalling is not an option. I do not have an external disk. Since I can't get the new mac to see the old one in target mode, I don't have any faith that an external disk would make a difference anyway.

That's about all I can think of right now. Thank you in advance for your help.