[Not an answer] Sorry if this is not in accordance with ROS ANSWERS common practices. I am ameteur.
I have encountered a similar error with turtlebot3_navigation (other packages like turtlebot3_gazebo work fine). I have run the same launch files days ago, and they worked like a charm. Currently no idea why this happens.
System setup : ubuntu 16.04 on Windows 10 and ros kinetic
Error messages:...
[roslaunch.config][INFO] 2020-05-09 11:20:48,209: loading config file /opt/ros/kinetic/share/turtlebot3_navigation/launch/turtlebot3_navigation.launch
[roslaunch][ERROR] 2020-05-09 11:20:48,211: Invalid roslaunch XML syntax: [Errno 13] Permission denied: '/opt/ros/kinetic/share/turtlebot3_navigation/launch/turtlebot3_navigation.launch'
[roslaunch][ERROR] 2020-05-09 11:20:48,224: The traceback for the exception was written to the log file
[roslaunch][ERROR] 2020-05-09 11:20:48,229: Traceback (most recent call last):
File "/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/__init__.py", line 306, in main
p.start()
File "/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 268, in start
self._start_infrastructure()
File "/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 217, in _start_infrastructure
self._load_config()
File "/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 132, in _load_config
roslaunch_strs=self.roslaunch_strs, verbose=self.verbose)
File "/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/config.py", line 453, in load_config_default
raise RLException(e)
RLException: Invalid roslaunch XML syntax: [Errno 13] Permission denied: '/opt/ros/kinetic/share/turtlebot3_navigation/launch/turtlebot3_navigation.launch'
...
I am trying to resolve this but unsuccessful so far.