Why do poly2trellis(.) returns error for standard generator polynomials?

I was trying to generate trellis for standard code convolutional code

>>trellis = poly2trellis(4,[74 64]) returns

???Error using ==> poly2trellis

Generator describes code of less than specified constraint length.

Infact poly2trellis(.) returns same error for a bunch of codes listed in Table on page 560 of Error Correction Coding: Mathematical Methods and Algorithms by Todd K. Moon.

What exactly am I missing here.