Problem new Signal Processing Block

Dear all,

I am trying to build a new signal processing block and I follow the
Eric B. tutorial on How to Write a new Signal Processing Block.
When I run make check or ./run_tests it works fine, however if I run
./ a receive the message

Traceback (most recent call last):
File “./”, line 24, in
import howto
File “/usr/lib/python2.6/dist-packages/”, line 6, in
import _howto
ImportError: No module named _howto

I using python 2.6 in Ubuntu 9.04 Jaunty. Can anyone help me?