[15:49:22 ERROR]: Could not pass event InventoryCreativeEvent to QuantumRPG v4.4.0
org.bukkit.event.EventException: null
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:316) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:66) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:507) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:492) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.PlayerConnection.a(PlayerConnection.java:2266) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.PacketPlayInSetCreativeSlot.a(SourceFile:23) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.PacketPlayInSetCreativeSlot.a(SourceFile:9) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.PlayerConnectionUtils.lambda$0(PlayerConnectionUtils.java:9) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_211]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_211]
        at net.minecraft.server.v1_13_R2.SystemUtils.a(SourceFile:199) [spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.MinecraftServer.b(MinecraftServer.java:896) [spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.DedicatedServer.b(DedicatedServer.java:417) [spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:831) [spigot.jar:git-Spigot-1a3504a-dfa7583]
        at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:729) [spigot.jar:git-Spigot-1a3504a-dfa7583]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
Caused by: java.lang.IllegalArgumentException: Cannot copy null stack
        at org.apache.commons.lang.Validate.notNull(Validate.java:192) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at org.bukkit.inventory.ItemStack.<init>(ItemStack.java:90) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        at su.nightexpress.quantumrpg.modules.ISocketGUI.replacePlaceholder(ISocketGUI.java:146) ~[?:?]
        at su.nightexpress.quantumrpg.modules.ISocketGUI.onCreate(ISocketGUI.java:101) ~[?:?]
        at su.jupiter44.jcore.gui.v3.JGUI.open(JGUI.java:128) ~[?:?]
        at su.nightexpress.quantumrpg.modules.ISocketGUI.open(ISocketGUI.java:117) ~[?:?]
        at su.nightexpress.quantumrpg.modules.QModuleRate.startSocketing(QModuleRate.java:116) ~[?:?]
        at su.nightexpress.quantumrpg.modules.refine.RefineManager.onRefineDragAndDrop(RefineManager.java:654) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_211]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:312) ~[spigot.jar:git-Spigot-1a3504a-dfa7583]
        ... 15 more