problem in running rosserial on raspberry

edit

I have installed rosserial on raspberry pi according to the instructions given in the following link
http://wiki.jigsawrenaissance.org/ROS...
On running roslaunch rosserial_server serial.launch port:=/dev/ttyACM0 following is showing ....

pi@raspberrypi ~ $ roslaunch rosserial_server serial.launch port:=/dev/ttyACM0
... logging to /home/pi/.ros/log/f8109b02-82a0-11e4-83ef-b827eb8371f7/roslaunch-raspberrypi-4607.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://raspberrypi:55941/

SUMMARY
========

PARAMETERS
 * /rosdistro
 * /rosserial_server/port
 * /rosversion

NODES
  /
    rosserial_message_info (rosserial_python/message_info_service.py)
    rosserial_server (rosserial_server/serial_node)

ROS_MASTER_URI=http://localhost:11311

core service [/rosout] found
process[rosserial_server-1]: started with pid [4653]
process[rosserial_message_info-2]: started with pid [4683]
Traceback (most recent call last):
  File "/home/pi/catkin_ws/src/rosserial/rosserial_python/nodes/message_info_service.py", line 46, in <module>
    from rosserial_python import load_message
  File "/home/pi/catkin_ws/devel/lib/python2.7/dist-packages/rosserial_python/__init__.py", line 34, in <module>
    exec(__fh.read())
  File "<string>", line 1, in <module>
  File "/home/pi/catkin_ws/src/rosserial/rosserial_python/src/rosserial_python/SerialClient.py", line 50, in <module>
    import diagnostic_msgs.msg
ImportError: No module named diagnostic_msgs.msg
[rosserial_message_info-2] process has died [pid 4683, exit code 1, cmd /home/pi/catkin_ws/src/rosserial/rosserial_python/nodes/message_info_service.py __name:=rosserial_message_info __log:=/home/pi/.ros/log/f8109b02-82a0-11e4-83ef-b827eb8371f7/rosserial_message_info-2.log].
log file: /home/pi/.ros/log/f8109b02-82a0-11e4-83ef-b827eb8371f7/rosserial_message_info-2*.log

What is the error? Thanks in advance