Invoking "make -j4 -l4" failed, ImportError: No module named 'em'

edit

Hi all,

After installing some rqt related packages, when running "catkin_make" I get:

make: *** [all] Error 2
Invoking "make -j4 -l4" failed

Examining the output I see

    Traceback (most recent call last):
  File "/opt/ros/indigo/share/gencpp/cmake/../../../lib/gencpp/gen_cpp.py", line 41, in <module>
Traceback (most recent call last):
  File "/opt/ros/indigo/share/gencpp/cmake/../../../lib/gencpp/gen_cpp.py", line 41, in <module>
    import genmsg.template_tools
  File "/opt/ros/indigo/lib/python2.7/dist-packages/genmsg/template_tools.py", line 39, in <module>
    import em
ImportError: No module named 'em'
    import genmsg.template_tools
  File "/opt/ros/indigo/lib/python2.7/dist-packages/genmsg/template_tools.py", line 39, in <module>
    import em

The error persists although I have ran both python2.7 -m pip install empy and sudo apt-get install python-empy

Anyone has any advise?

Thanks