I tried to remove the muffler and this error appears, how can I solve it?

`Callframe at: table.insert
function: SilencerLoading.lua -- file: SilencerLoading.lua line # 12 | MOD: Silencer
java.lang.NullPointerException: Cannot invoke "se.krka.kahlua.vm.KahluaTable.len()" because "<local2>" is null
at se.krka.kahlua.stdlib.TableLib.insert(TableLib.java:217)
at se.krka.kahlua.stdlib.TableLib.call(TableLib.java:89)
at se.krka.kahlua.vm.KahluaThread.callJava(KahluaThread.java:182)
at se.krka.kahlua.vm.KahluaThread.luaMainloop(KahluaThread.java:1007)
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.pcall(KahluaThread.java:1782)
at se.krka.kahlua.integration.LuaCaller.pcall(LuaCaller.java:76)
at se.krka.kahlua.integration.LuaCaller.protectedCall(LuaCaller.java:117)
at zombie.Lua.LuaManager.RunLuaInternal(LuaManager.java:564)
at zombie.Lua.LuaManager.RunLua(LuaManager.java:510)
at zombie.Lua.LuaManager.RunLua(LuaManager.java:496)
at zombie.Lua.LuaManager.LoadDirBase(LuaManager.java:342)
at zombie.Lua.LuaManager.LoadDirBase(LuaManager.java:264)
at zombie.gameStates.GameLoadingState.enter(GameLoadingState.java:97)
at zombie.gameStates.GameStateMachine.update(GameStateMachine.java:145)
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)
`