Controller Spawner couldn't reach controller_manager to take down controllers

edit

When I Tried this tutorial http://gazebosim.org/tutorials?tut=ro..., the result output of the rrbot_control.launch terminal was always as follows:

[INFO] [WallTime: 1431386440.414532] [0.000000] Controller Spawner: Waiting for service controller_manager/load_controller
[INFO] [WallTime: 1431386440.421600] [0.000000] Controller Spawner: Waiting for service controller_manager/switch_controller
[INFO] [WallTime: 1431386440.427941] [0.000000] Controller Spawner: Waiting for service controller_manager/unload_controller
[INFO] [WallTime: 1431386440.436520] [0.000000] Loading controller: joint_state_controller
[INFO] [WallTime: 1431386441.193234] [20.148000] Loading controller: joint1_position_controller
[INFO] [WallTime: 1431386441.691031] [20.635000] Loading controller: joint2_position_controller
[INFO] [WallTime: 1431386441.803746] [20.722000] Controller Spawner: Loaded controllers: joint_state_controller, joint1_position_controller, joint2_position_controller
Traceback (most recent call last):
  File "/home/comex/catkin_ws/src/ros_control/controller_manager/scripts/spawner", line 212, in <module>
    if __name__ == '__main__': main()
  File "/home/comex/catkin_ws/src/ros_control/controller_manager/scripts/spawner", line 204, in main
    resp = switch_controller(loaded, [], 2)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 435, in __call__
    return self.call(*args, **kwds)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 525, in call
    raise ServiceException("transport error completing service call: %s"%(str(e)))
rospy.service.ServiceException: transport error completing service call: unable to receive data from sender, check sender's logs for details
[INFO] [WallTime: 1431386459.030696] [20.728000] Shutting down spawner. Stopping and unloading controllers...
[WARN] [WallTime: 1431386490.032891] [20.728000] Controller Spawner couldn't reach controller_manager to take down controllers. Waited for 30 second(s).

I couldn't figure out why this always happen. I use Ubuntu 14.04 and gazebo 2.2.3 with ROS Indigo.Can someone help?