[Erratic Robot] unable to launch this package!

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Hi all

I am looking to launch the erratic robot I downloaded from (Am I using the outdated package?)

sudo apt-get install ros-groovy-erratic-robot

then execute:

roslaunch erratic_navigation_apps demo_2dnav_slam.launch

But I got the following errorS from gazebo:

 Error [parser.cc:712] XML Element[filename], child of element[mesh] not defined in SDF. Ignoring.[mesh]

    Error [parser.cc:703] Error reading element <mesh>

    Error [parser.cc:703] Error reading element <geometry>

    Error [parser.cc:703] Error reading element <collision>

    Error [parser.cc:703] Error reading element <link>

    Error [parser.cc:703] Error reading element <model>

    Error [parser.cc:703] Error reading element <world>

    Error [parser.cc:369] Unable to read element <sdf>

    Error:   Could not find the 'robot' element in the xml file

             at line 59 in /tmp/buildd/ros-groovy-urdfdom-0.2.7-0precise-20130326-0224/urdf_parser/src/model.cpp

    Error [parser_urdf.cc:1814] Unable to call parseURDF on robot model

    Warning [parser.cc:377] SDF has no <sdf> element in file[urdf file]

    Error [parser.cc:291] parse as old urdf model file failed.

    Error [Server.cc:253] Unable to read sdf file[/opt/ros/groovy/stacks/simulator_gazebo/gazebo_worlds/worlds/wg_collada.world]

    Segmentation fault (core dumped)

    [gazebo-1] process has died [pid 19218, exit code 139, cmd /opt/ros/groovy/stacks/simulator_gazebo/gazebo/scripts/gazebo -u /opt/ros/groovy/stacks/simulator_gazebo/gazebo_worlds/worlds/wg_collada.world __name:=gazebo __log:=/home/dijia/.ros/log/1e527878-d52b-11e2-83e6-d0df9ada3503/gazebo-1.log].

    log file: /home/abc/.ros/log/1e527878-d52b-11e2-83e6-d0df9ada3503/gazebo-1*.log