[Tinyos-help] segment error about learning TOSSIM

[CrazyPenguin]

Hello all,
I am studying follow this
http://docs.tinyos.net/index.php/TOSSIM#Configuring_a_Network . And when
I learning about  its 5.Configuring a Network , and running the
python_test.py script, my  result is different(get a segment error at
the end and can't find the receive displaying) from the example on the
page:
crazypenguin at debian:/opt/tinyos-2.1.0/apps/RadioCountToLeds
$ ./python_test.py 
  1   2   -54.0
  2   1   -55.0
  1   3   -60.0
  3   1   -60.0
  2   3   -64.0
  3   2   -64.0
Creating noise model for  1
Creating noise model for  2
Creating noise model for  3
DEBUG (1): Application booted.
DEBUG (1): Application booted again.
DEBUG (1): Application booted a third time.
DEBUG (2): Application booted.
DEBUG (2): Application booted again.
DEBUG (2): Application booted a third time.
DEBUG (3): Application booted.
DEBUG (3): Application booted again.
DEBUG (3): Application booted a third time.
DEBUG (1): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (1): RadioCountToLedsC: packet sent.
DEBUG (2): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (2): RadioCountToLedsC: packet sent.
DEBUG (3): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (3): RadioCountToLedsC: packet sent.
段错误 (segment error)

and this result seems like the details on the page :
If you set node's clear channel assessment to be at -110dBm, then nodes
will never transmit, as noise and interference never drop this low.
You'll see something like this:

1  2 -54.0
2  1 -55.0
1  3 -60.0
3  1 -60.0
2  3 -64.0
3  2 -64.0
DEBUG (1): Application booted.
DEBUG (1): Application booted again.
DEBUG (1): Application booted a third time.
DEBUG (2): Application booted.
DEBUG (2): Application booted again.
DEBUG (2): Application booted a third time.
DEBUG (3): Application booted.
DEBUG (3): Application booted again.
DEBUG (3): Application booted a third time.
DEBUG (1): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (1): RadioCountToLedsC: packet sent.
DEBUG (2): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (2): RadioCountToLedsC: packet sent.
DEBUG (3): RadioCountToLedsC: timer fired, counter is 1.
DEBUG (3): RadioCountToLedsC: packet sent.
DEBUG (1): RadioCountToLedsC: timer fired, counter is 2.
DEBUG (2): RadioCountToLedsC: timer fired, counter is 2.
DEBUG (3): RadioCountToLedsC: timer fired, counter is 2.

But I really can't find any thoughts in my head , please help me.