Problems with Viterbi decoding

[bitwisebill]

Greetings all,

I'm trying to implement a decoder for NXDN in GRC and the Viterbi decoding is not cooperating with me. I'm wondering if one of you could please take a few minutes to look this over and see if you could point out where I have gone wrong, because I am thoroughly puzzled by this. Any insight would be highly, highly appreciated.
I've pulled all the parameters and the input testing data straight from the NXDN technical specs so I'm really at a loss here.

ECC parameters: K=5, R=1/2, G1= 1 + x^3 + x^4, G2= 1 + x + x^2 + x^4
Trellis permutation: size 252, (0,21,42,63,84,105,126,147,168,189,210,231,1,...)
FSM constructor: trellis.fsm(2,1,[0b11001,0b10111])
Block size 252, initial state 0, final state 0

Input data: 1410 0024 0154 0404 a120 6088 0224 0004 8280 4d14 0340 0019 4101 9240 1ec2 40b
Correct decoding: 0101 0020 0001 0001 0000 0000 00
My decoding:      0606 00c0 0006 0006 0000 0000 00

Many thanks in advance!