urdf_parser_py fails when processing a URDF containing a element
which adheres to the current specification given in
http://wiki.ros.org/urdf/XML/Transmission .
Because the old specification expected a "type" attribute,
which the new spec includes as a sub-element, the python parser throws "type"-is-missing Exceptions.
Also, the actuator definition became more complex and now includes the mechanicalReduction parameter.

As a temporary fix it's enough to comment the following in urdf.py over here:

xmlr.reflect(Transmission, tag = 'transmission', params = [
        name_attribute,
#       xmlr.Attribute('type', str),
#       xmlr.Element('joint', 'element_name'),
#       xmlr.Element('actuator', 'element_name'),
#       xmlr.Element('mechanicalReduction', float)
        ])

This works over here, because we never access the transmission definitions via urdfdom, but obviously it's just a hot fix, nothing more..

Because it's not possible to quickly overlay this ros-code in a uniform local workspace
(you just recently removed catkin support...),
it's pretty important to me to see this fixed in the official ros (ubuntu) packages soon

• one way or the other.