I'm a new player and don't know how to read the log to fix a possible problem, nor do i know if this log is anything i should worry about.

I will be thankful for any help

`attempted index: items of non-table: true
function: DefUbWallsServer.lua -- file: DefUbWallsServer.lua line # 66 | MOD: Unbreakable Metal Walls v1.4
java.lang.RuntimeException: attempted index: items of non-table: true
at se.krka.kahlua.vm.KahluaThread.tableget(KahluaThread.java:1689)
at se.krka.kahlua.vm.KahluaThread.luaMainloop(KahluaThread.java:492)
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)
`