Re:Problem in using trellis Error correction en- and decoder

Hello Achilleas.
Forgiveness for mysticism about the example.
is interference_cancellation.grc (GNU Radio Companion 3.2.2)

/usr/share/gnuradio/examples/grc/trellis/interference_cancellation.grc

the error:
[error]
Loading:
“/usr/share/gnuradio/examples/grc/trellis/interference_cancellation.grc”

Done

Showing:
“/usr/share/gnuradio/examples/grc/trellis/interference_cancellation.grc”

Generating:
“/usr/share/gnuradio/examples/grc/trellis/int_cancellation.py”

Warning: This flow graph may not have flow control: no audio or usrp blocks
found. Add a Misc->Throttle block to your flow graph to avoid CPU congestion.

Generating:
“/usr/share/gnuradio/examples/grc/trellis/int_cancellation.py”

Warning: This flow graph may not have flow control: no audio or usrp blocks
found. Add a Misc->Throttle block to your flow graph to avoid CPU congestion.

Executing:
“/usr/share/gnuradio/examples/grc/trellis/int_cancellation.py”

terminate called after throwing an instance of ‘std::runtime_error’
what(): fsm::fsm(const char *name): file open error

Done
[/error]

i change the path to absolute path, but don’t work.
the file exist in this directory. i no try to add a Throttle block.

i do not care if the example doesn’t work, be cause i don’t get this
error in my work.
I must have to go now. sorry.
thanks for the fast reply.