Error running move_base in navigation stack

Hi, I am trying to run the ROS navigation stack to take input from two Hokuyo laser sensors and output velocity commands to a robot according to a set goal. I have set up the navigation stack as in the ROS tutorials http://wiki.ros.org/navigation/Tutorials/RobotSetup/ except that instead of running the AMCL package, I am using gmapping to localise the robot and create a global map. My launch files are: wheelchair_config.launch and move_base.launch In the yaml configuration files, I have followed the guidelines set out in the tutorial linked above: - in common config yaml: two laser sensors for my observation sources, robot footprint set up as a rectangle - in global costmap config yaml: global frame = /map, robot_base_frame = /base_link, static_map =false - in local costmap config yaml: global frame = /odom, robot_base_frame = /base_link, static_map = false, rolling_window = true - base local planner yaml identical to tutorial example When I launch the wheelchair config file, the laser data and transforms appear as expected in rviz. When I then launch the move base file, the gmapping node seems to set up correctly and outputs a map in rviz as expected but I get an error with the move_base node. process[move_base-2]: started with pid [28781] terminate called after throwing an instance of 'boost::exception_detail::clone_impl>' what(): boost: mutex lock failed in pthread_mutex_lock: Invalid argument [move_base-2] process has died [pid 28781, exit code -6, cmd /opt/ros/indigo/lib/move_base/move_base __name:=move_base __log:=/home/steph/.ros/log/a82bb134-6cd4-11e5-9cc0-88532ea048df/move_base-2.log]. log file: /home/steph/.ros/log/a82bb134-6cd4-11e5-9cc0-88532ea048df/move_base-2*.log If I try to proceed to send goals to the navigation stack (despite the error as above) as instructed in the tutorial http://wiki.ros.org/navigation/Tutorials/SendingSimpleGoals I get an output message stating [ INFO] [1444210927.061683327]: Waiting for the move_base action server to come up which makes me think the move_base node was perhaps not initiated correctly. Does anyone know what causes this error when running the move base package? And is it likely that this error is the reason why the move base action server does not come up? Thank you. Addit: After trying to break down my process further, it seems that move_base crashes when I try to launch either my transform file or gmapping, which makes me think the problem is somehow being caused by my transforms? My tf.launch file is