Solved a bug: the map topic remapping was invalid.

launch/include/move_base.launch

@@ -27,7 +27,7 @@
           name="$(arg move_base_name)"
           output="$(arg output)"
           launch-prefix="$(arg launch_prefix)">
-      <remap from="/map"    to="$(arg map_topic)" />
+      <remap from="map"    to="$(arg map_topic)" />
       <remap from="cmd_vel" to="$(arg cmd_vel_topic)" />
       <remap from="odom"    to="$(arg odom_topic)" />
       <remap from="move_base_simple/goal"    to="$(arg move_base_name)_simple/goal" />