Problem with urdf_tutorial

edit

Hi All,

I am going through the urdf tutorials but have run into a problem. I got to Materials before running into this error:

Traceback (most recent call last):
File "/opt/ros/indigo/share/xacro/xacro.py", line 62, in <module>
xacro.main()
File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 673, in main
f = open(args[0])
IOError: [Errno 2] No such file or directory: 'urdf/04-materials.urdf'
Invalid <param> tag: Cannot load command parameter [robot_description]: command [/opt/ros/indigo/share/xacro/xacro.py urdf/04-materials.urdf] returned with code [1]. 

Param xml is <param command="$(find xacro)/xacro.py $(arg model)" name="robot_description"/>
The traceback for the exception was written to the log file

The file does exist and I'm not even using xacro yet. The weirdest part is I was able to get the first 3 files to work (myfirst, multiple, and origins) without this issue, but now they give me the same error and won't run. I've seen a few similar issues here and people say to go through the xml in the xacro file, but as I've said I don't have one. Anyone know why this is happening?

[EDIT] After finding that the master and indigo branches of the urdf_tutorial package are different on github, I deleted the master and downloaded the indigo version. This got rid of the xacro issue but still tells me that the file doesn't exist. This happens with both roslaunch urdf_tutorial display.launch model:=urdf/04-materials.urdf from the package path as shown in the tutorial and when using roslaunch urdf_tutorial display.launch model:='$(find urdf_tutorial)/urdf/04-materials.urdf'. The full error message is shown below:

Traceback (most recent call last):
File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/__init__.py", line 307, in main
p.start()
File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 268, in start
self._start_infrastructure()
File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 217, in _start_infrastructure
self._load_config()
File "/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/parent.py", line 132, 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 ...