ImportError: No module named rospkg

edit

I am trying to run fake_turtlebot.launch. I keep getting:

Traceback (most recent call last):
  File "/opt/ros/indigo/share/xacro/xacro.py", line 60, in <module>
    import xacro
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 45, in <module>
    from roslaunch import substitution_args
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/__init__.py", line 48, in <module>
    import rospkg
ImportError: No module named rospkg
Invalid <param> tag: Cannot load command parameter [robot_description]: command [/opt/ros/indigo/share/xacro/xacro.py '/home/brent/catkin_ws/src/rbx1/rbx1_description/urdf/turtlebot.urdf.xacro'] returned with code [1]. 

Param xml is <param command="$(arg urdf_file)" name="robot_description"/>
The traceback for the exception was written to the log file
brent@brent-Dell-DM051:~$

I thing that my pythonpath is set wrong, but I am not sure how to fix it. Thank you