Hi, I am trying to install ROS indigo on Ubilinux - Edison following this tutorial. I symlinked /opt and /var/cache/apt to 2 folders in a microSD card in order to make room for the desktop package. It all went through up to: 2.3 Building the catkin Workspace. I have this error message:

==> Processing catkin package: 'catkin'
==> cmake /root/ros_catkin_ws/src/catkin -DCATKIN_DEVEL_PREFIX=/root/ros_catkin_ws/devel_isolated/catkin -DCMAKE_INSTALL_PREFIX=/opt/ros/indigo -DCMAKE_BUILD_TYPE=Release -G Unix Makefiles in '/root/ros_catkin_ws/build_isolated/catkin'
-- Using CATKIN_DEVEL_PREFIX: /root/ros_catkin_ws/devel_isolated/catkin
-- Using CMAKE_PREFIX_PATH: 
-- Using PYTHON_EXECUTABLE: /usr/bin/python
-- Using Debian Python package layout
-- Could NOT find PY_em (missing:  PY_EM) 
CMake Error at cmake/empy.cmake:29 (message):
  Unable to find either executable 'empy' or Python module 'em'...  try
  installing the package 'python-empy'
Call Stack (most recent call first):
  cmake/all.cmake:146 (include)
  CMakeLists.txt:8 (include)


-- Configuring incomplete, errors occurred!
<== Failed to process package 'catkin': 
  Command 'cmake /root/ros_catkin_ws/src/catkin -DCATKIN_DEVEL_PREFIX=/root/ros_catkin_ws/devel_isolated/catkin -DCMAKE_INSTALL_PREFIX=/opt/ros/indigo -DCMAKE_BUILD_TYPE=Release -G Unix Makefiles' returned non-zero exit status 1

Reproduce this error by running:
==> cd /root/ros_catkin_ws/build_isolated/catkin && cmake /root/ros_catkin_ws/src/catkin -DCATKIN_DEVEL_PREFIX=/root/ros_catkin_ws/devel_isolated/catkin -DCMAKE_INSTALL_PREFIX=/opt/ros/indigo -DCMAKE_BUILD_TYPE=Release -G Unix Makefiles

Command failed, exiting.

Now my folder structure is: ~/roscatkinws rather than /root/roscatkinws. I don't know if this could be the main problem or if the missing PY_emvisgenerating the error.

Thank you in advance, Marcello