大佬，为什么我开不了几枪就会出现下面的报错

`attempted index: removeFromSquare of non-table: null
function: itemremove -- file: Advanced_trajectory_core.lua line # 21 | MOD: 进阶弹道改AdvancedTrajectoryW
function: checkontick -- file: Advanced_trajectory_core.lua line # 560 | MOD: 进阶弹道改AdvancedTrajectoryW
java.lang.RuntimeException: attempted index: removeFromSquare of non-table: null
at se.krka.kahlua.vm.KahluaThread.tableget(KahluaThread.java:1689)
at se.krka.kahlua.vm.KahluaThread.luaMainloop(KahluaThread.java:641)
at se.krka.kahlua.vm.KahluaThread.call(KahluaThread.java:163)
at se.krka.kahlua.vm.KahluaThread.pcall(KahluaThread.java:1980)
at se.krka.kahlua.vm.KahluaThread.pcallvoid(KahluaThread.java:1812)
at se.krka.kahlua.integration.LuaCaller.pcallvoid(LuaCaller.java:66)
at se.krka.kahlua.integration.LuaCaller.protectedCallVoid(LuaCaller.java:139)
at zombie.Lua.Event.trigger(Event.java:64)
at zombie.Lua.LuaEventManager.triggerEvent(LuaEventManager.java:92)
at zombie.gameStates.IngameState.updateInternal(IngameState.java:1624)
at zombie.gameStates.IngameState.update(IngameState.java:1333)
at zombie.gameStates.GameStateMachine.update(GameStateMachine.java:101)
at zombie.GameWindow.logic(GameWindow.java:298)
at zombie.core.profiling.AbstractPerformanceProfileProbe.invokeAndMeasure(AbstractPerformanceProfileProbe.java:71)
at zombie.GameWindow.frameStep(GameWindow.java:765)
at zombie.GameWindow.run_ez(GameWindow.java:681)
at zombie.GameWindow.mainThread(GameWindow.java:495)
at java.base/java.lang.Thread.run(Unknown Source)
`