Hello Achilleas A.
Sorry for my delay.
Well,I try to start the example (interference_cancellation.grc) but do
not succeed.
I put the trotle and then the warning disappears, but the error not.
I installed the gnuradio by synaptic.
in ubuntu, i think the “Program Files directory” is “/usr/share/”.
Prefix = “/usr/share/gnuradio/”
Now it’s works!!! 
Well, Now we know that the example works (with a little modifications).
I have fear of being wrong with regard to the functioning of the FSM.
How we operate my trellis?
I see that my file stop when i use files. why?
(my file= http://img213.imageshack.us/img213/3435/pantallazoxe.png)
I’m area of knowledge is not precisely electronics/telecommunications.
i’m programmer, but i’m here. haha
i read about TCM, and CC (the theory).
Which finite state machine allows me to copy a file?
where I can get such information?
Thanks!!