There is an error that must solved:

1- make sure u leave no "enter"  in grammer file .

2- the grammer file is not the one is used in here, so u have to complete it , for me I used 

S : NS_B CALL NAME_LOOP NS_E

NAME_LOOP: NAME_LOOP NAME

NAME_LOOP: NAME

S : NS_B DIAL DIGIT_LOOP NS_E

DIGIT_LOOP: DIGIT_LOOP DIGIT

DIGIT_LOOP: DIGIT

with no enter in between lines and the error is solved

this is a beginner's solution to  a problem i faced with mkdfa.pl sample