Problem with keyboard_teleop in ROS by Example

edit

I learnt ROS By Example recently,and I have some problem with keyboard_teleop.launch

roslaunch rbx1_nav keyboard_teleop.launch

The launch file:

    <launch>

  <node pkg="turtlebot_teleop" type="turtlebot_teleop_key" name="turtlebot_teleop_keyboard" output="screen">
    <param name="scale_linear" value="0.1" type="double"/>
    <param name="scale_angular" value="0.4" type="double"/>
    <remap from="turtlebot_teleop_keyboard/cmd_vel" to="cmd_vel" />
  </node>

</launch>

However , I run this launch ,the terminal shows

ERROR: cannot launch node of type [turtlebot_teleop/turtlebot_teleop_key]: can't locate node [turtlebot_teleop_key] in package [turtlebot_teleop]

Before I run this launch ,I run

roslaunch rbx1_bringup fake_turtlebot.launch
rosrun rviz rviz -d `rospack find rbx1_nav`/sim.rviz

How to fix it?

Thanks