Unable to select model argument for urdf-tutorial package

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Hi!

I'm looking into the tutorials on URDF (ROS Indigo), robot_state_publisher etc. In this tutorial it is stated that

roslaunch urdf_tutorial display.launch model:=urdf/01-myfirst.urdf

should start rviz (launch parameters stored inside display.launch) with the selected model. Sadly I'm getting the error that such file cannot be found:

rosuser:~$ roslaunch urdf_tutorial display.launch model:=urdf/01-myfirst.urdf
... logging to /home/rosuser/.ros/log/336d620e-8d02-11e5-b0c5-90fba64806be/roslaunch-latadmin-ros-7550.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

Traceback (most recent call last):
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/__init__.py", line 298, in main
    p.start()
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 260, in start
    self._start_infrastructure()
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 209, in _start_infrastructure
    self._load_config()
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 124, in _load_config
    roslaunch_strs=self.roslaunch_strs, verbose=self.verbose)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/config.py", line 451, in load_config_default
    loader.load(f, config, verbose=verbose)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 730, in load
    self._load_launch(launch, ros_config, is_core=core, filename=filename, argv=argv, verbose=verbose)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 702, in _load_launch
    self._recurse_load(ros_config, launch.childNodes, self.root_context, None, is_core, verbose)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 646, in _recurse_load
    self._param_tag(tag, context, ros_config, verbose=verbose)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 95, in call
    return f(*args, **kwds)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 264, in _param_tag
    value = self.param_value(verbose, name, ptype, *vals)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/loader.py", line 463, in param_value
    with open(textfile, 'r') as f:
IOError: [Errno 2] No such file or directory: u'urdf/01-myfirst.urdf'

I also read the lines below:

This launch file assumes that 01-myfirst.urdf is in the urdf subdirectory of the directory that you type the command in. Otherwise, you should say model:='$(find pkg-name)/urdf/01-myfirst.urdf' where pkg-name is the name of the package that the file is in (single quotes required)

I tried both with an installed version of the package and a fresh download of the package inside my catkin workspace but in both cases I'm getting the same error. I have checked and the urdf folder is there along with the specified file (last line of the following terminal output):

rosuser:/opt/ros/indigo/share/urdf_tutorial$ ls -R
.:
cmake  images  launch  package.xml  urdf  urdf.rviz  urdf.vcg

./cmake:
urdf_tutorialConfig-version.cmake  urdf_tutorialConfig.cmake

./images:
flexible.png  materials.png  multipleshapes.png  myfirst.png  origins.png  visual.png

./launch:
display.launch  gazebo.launch  xacrodisplay.launch

./urdf:
01-myfirst.urdf  02-multipleshapes.urdf  03-origins.urdf  04-materials.urdf  05-visual.urdf  06-flexible ...