Each manifest.xml in the model database points to a model.sdf file, but that file is in the URDF format, not SDF.
minor typo fix
It looks like the affected model database files are: drc_robot, irobot_hand, sandia_hand, sandia_hand_left, and sandia_hand_right.
is renaming the file to model.urdf sufficient fix for this issue?
pull request #47