Not sure what it is , but :
`function: 1503MCTCGMusicDefenitionsTCBoombox.lua -- file: 1503MCTCGMusicDefenitionsTCBoombox.lua line # 3 | MOD: Custom Songs
java.lang.RuntimeException: attempted index of non-table
at se.krka.kahlua.vm.KahluaUtil.fail(KahluaUtil.java:82)
at se.krka.kahlua.vm.KahluaUtil.luaAssert(KahluaUtil.java:70)
at se.krka.kahlua.vm.KahluaThread.tableSet(KahluaThread.java:1726)
at se.krka.kahlua.vm.KahluaThread.luaMainloop(KahluaThread.java:594)
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.Lua.LuaManager.LoadDirBase(LuaManager.java:391)
at zombie.core.Core.ResetLua(Core.java:4170)
at zombie.gameStates.ConnectToServerState.receiveServerOptions(ConnectToServerState.java:131)
at zombie.gameStates.ConnectToServerState.Finish(ConnectToServerState.java:688)
at zombie.gameStates.ConnectToServerState.update(ConnectToServerState.java:100)
at zombie.gameStates.MainScreenState.update(MainScreenState.java:523)
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)
`