Why does robot_model fail in rosinstall

edit

I get the following when rosinstall hits the robot_model line in .rosinstall:

- hg: {local-name: robot_model, uri: 'https://kforge.ros.org/robotmodel/robot_model',
    version: robot_model-1.4.0}

This despite having Mercurial installed via macports and having several other hg lines in my .rosinstall which install fine. What's going on?

Installing https://kforge.ros.org/robotmodel/robot_model robot_model-1.4.0 to /Users/my_name/ros/robot_model
Traceback (most recent call last):
  File "/usr/local/bin/rosinstall", line 5, in <module>
    pkg_resources.run_script('rosinstall==0.5.16', 'rosinstall')
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py", line 442, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py", line 1167, in run_script
    exec script_code in namespace, namespace
  File "/Library/Python/2.6/site-packages/rosinstall-0.5.16-py2.6.egg/EGG-INFO/scripts/rosinstall", line 556, in <module>

  File "/Library/Python/2.6/site-packages/rosinstall-0.5.16-py2.6.egg/EGG-INFO/scripts/rosinstall", line 534, in rosinstall_main

  File "/Library/Python/2.6/site-packages/rosinstall-0.5.16-py2.6.egg/EGG-INFO/scripts/rosinstall", line 276, in execute_install

  File "/Library/Python/2.6/site-packages/rosinstall-0.5.16-py2.6.egg/EGG-INFO/scripts/rosinstall", line 115, in install

AttributeError: VCSClient instance has no attribute 'type'