SITL encounters error while it simulates fixed wing

Hey,guys.
I am using v1.13.0 and I encounter errors while it runs for gazebo_plane. But everything is OK when it runs for gazebo_standard_vtol. What makes the error? Thank you.
the error:

PX4 SIM HOST: localhost

INFO [simulator] Waiting for simulator to accept connection on TCP port 4560

INFO [simulator] Simulator connected on TCP port 4560.

INFO [commander] LED: open /dev/led0 failed (22)

INFO [init] Mixer: etc/mixers-sitl/plane_sitl.main.mix on /dev/pwm_output0

INFO [init] setting PWM_AUX_OUT none

/Users/kevin/PX4-Autopilot/build/px4_sitl_default/tmp/rootfs/etc/init.d/rc.fw_apps: line 44: syntax error near unexpected token `then'

ERROR [px4] Startup script returned with return value: 512

Can you describe your hardware setup in running Px4-SITL with Gazebo.