Just reading the instructions made it seem like a daunting task, but I kept getting that stupid error and before returning I thought I'd give it a shot. So far so good and I'm really happy with this phone. The speeds are incredible (although battery life not so much ^_^ but at least it doesn't go from 100% to 50% in 4 hours like the Triumph. And that was without even barely touching the phone)
If you're getting that error do the s-off and then follow the "turn your phone into an evo3d" thread.