Hi,
it's been a while ago since i've set up my tricopter. But i'm quiet sure i had the same problems on arming the board.
I went trough this guid over and over again:
http://rcexplorer.se/Educational/kkguide/kkguide/tri.html
But i was not able to arm the board.
Somehow (and i don't know what exactly it was) it worked after i tested every esc on the receiver directly. I entered the setup mode for every esc but did not change any setting. After that connected again the flight controller board and at that point everything was fine (only a gyro compensation direction needed to be changed after that).
Maybe you'll give it a last try before trowing the board away ;-)
Cheers, Gregor