Somebody else had the same issue, see http://www.voxforge.org/home/dev/acousticmodels/linux/create/htkjulius/tutorial/triphones/step-10/comments/error-find-proto - see if it helps and if not why your situation is different. It comes down to adding audio samples with b in it.

thanks for response 

instead of trying for fulllist0 to get result for unseen data ,

i try this on triphone1 AND even monophone1 hmm9;

it is giving another problem that it is taking word YOUNG as phone in monophones0 and monophones1.

i m using beep dict .

Also i tried voxforgedict still facing the same problem,if i delete YOUNG from monophones it didnt work ,stuck at initial steps.

please help