Messages aren't built

edit

I've downloaded a ROS package and I would like to use its messages in my program, however, for some weird reason the messages aren't built and thus I get an error.

My package.xml has this:

<exec_depend>nerian_stereo</exec_depend>

my CMakeLists.txt has this:

find_package(catkin REQUIRED COMPONENTS
  rospy
  message_runtime
  std_msgs
  nerian_stereo
)

and my code file has this:

from nerian_stereo import * 
self.camera_info = rospy.Subscriber("/nerian_stereo/stereo_camera_info", StereoCameraInfo ,self.stereo_camera_cb)

however I still get this annoying error of:

NameError: global name 'StereoCameraInfo' is not defined

What's wrong? I also observed my catkin_make and I see that this package is not built at all, the output does not show its name. Is there yet another file which needs to be edited?

EDIT: Here is the message: http://docs.ros.org/api/nerian_stereo...