With your last suggestion it worked! thank you so much! just a thing... the following step is not very clear for me (sorry, I'm new to this kind of things )
6. install ws4py:
sudo mkdir /opt/ws4py
sudo chown user:user /opt/ws4py # !!! you must change user on your system login!
at the end of the 5. step, I'm currently in the libindipython dir. Shall I have to change the dir or follow the step as I read them? and I don't understand # !!! you must change user on your system login! ... Sorry again