A headless linux server report an error

```
69945.475 Error MainLoop.cpp:1284: Exception at tick 37148045: The mod AAI Programmable Vehicles (0.7.22) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event aai-programmable-vehicles::load-unit-group-2 (ID 220)
__aai-programmable-vehicles__/control.lua:3560: attempt to index field 'cursor_stack' (a nil value)
stack traceback:
__aai-programmable-vehicles__/control.lua:3560: in function 'on_load_unit_group'
__aai-programmable-vehicles__/control.lua:3570: in function 'callback'
__aai-programmable-vehicles__/scripts/event.lua:14: in function <__aai-programmable-vehicles__/scripts/event.lua:12>
69945.475 Error ServerMultiplayerManager.cpp:92: MultiplayerManager failed: "The mod AAI Programmable Vehicles (0.7.22) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event aai-programmable-vehicles::load-unit-group-2 (ID 220)
__aai-programmable-vehicles__/control.lua:3560: attempt to index field 'cursor_stack' (a nil value)
stack traceback:
__aai-programmable-vehicles__/control.lua:3560: in function 'on_load_unit_group'
__aai-programmable-vehicles__/control.lua:3570: in function 'callback'
__aai-programmable-vehicles__/scripts/event.lua:14: in function <__aai-programmable-vehicles__/scripts/event.lua:12>"
69945.475 Info ServerMultiplayerManager.cpp:795: updateTick(37148045) changing state from(InGame) to(Failed)
69945.475 Quitting: multiplayer error.
69947.744 Info ServerMultiplayerManager.cpp:141: Quitting multiplayer connection.
69947.744 Info ServerMultiplayerManager.cpp:795: updateTick(4294967295) changing state from(Failed) to(Closed)
69947.746 Info UDPSocket.cpp:218: Closing socket
69947.746 Info UDPSocket.cpp:248: Socket closed
69947.746 Info UDPSocket.cpp:218: Closing socket
69948.161 Info UDPSocket.cpp:218: Closing socket
69948.161 Info UDPSocket.cpp:248: Socket closed
69948.162 Goodbye

```

So how can I prevent this error?