Why there is no window show after I run the camera_calibration node?

edit

After I run the node "camera_calibration" like this:

rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.108 image:=/pgr_camera/image_raw camera:=/pgr_camera

it shows as below:

Waiting for service /pgr_camera/set_camera_info ... 

OK 

*** Added sample 1, p_x = 0.897, p_y = 0.349, p_size = 0.277, skew = 0.027

Segmentation fault

Is there any one who can tell me why?

I am using electric on Ubuntu 10.04.And when I run the node "camera_calibration",there is no checkerboard in front of the camera.