Re:
I had the same problem (Attention 129) with my Dish Now receiver and got the new Smart Card to work after multiple tries. I tried automated activation and called customer service 4 times in about 24 hours. Each time the customer service representative was quickly telling me they would send back the signal to the box and that it would work within 15-20 minutes. Each time nothing happened and I was stucked with the Attention 129 message.
How I made it work .....
I think the reason it was not working was that my box was not up to date. Once I got the box to update, the new card was authorized the first time the signal was sent. So I think once you update your box to the latest software version, activation should work.
To make it work, I first reinstalled my old Smart Card into my receiver in order to be able to access the menus. I went into the setting menus and loaded some pages, I verified that auto-updates where active and loaded the system info page and played with switch tests, etc. While doing that after a switch test (I think) my receiver froze (as it also happened to someone how posted in this thread I think).
When the receiver froze I had to disconnect it (I had tried disconnecting the receptor before but it never triggered the update) when I reconnected the receiver it did not power on but this time started showing a message saying it was downloading an update. It only updated after it froze ... before that it never went into the update mode.
Once the update was completed the receiver (with the old Smart Card in) it showed me a new error message saying my Smartcard was not supported anymore and that I needed the new G3 Smartcard. I thought the problem was solved and that I only had to switch to the new G3 card now. I swapped the Smartcards, receiver accepted it but quickly reverted to the Attention 129 message.
This time, I called customer service, got the customer representative to send the signal once again ....... and this time it worked instantly while I was talking with the rep on the phone I saw the congratulation message, etc. Channels where not working though (black screen), the customer rep. suggested to unplug the receiver for 30 seconds. Did it. It solved the black screen problem and everything it now working perfectly.