Problem z perworldinventory

Witam od pewnego czasu mam problem z pluginem perworldinventory wyskakuje mi ten błąd proszę o pomoc :

[23:04:31 WARN]: Exception in thread "pool-3-thread-2"
[23:04:31 WARN]: org.apache.commons.lang.UnhandledException: Plugin PerWorldInventory v2.2.1 generated an exception while executing task 68
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NoSuchFieldError: PLAYER_HEAD
at me.ebonjaeger.perworldinventory.serialization.ItemSerializer.serialize(ItemSerializer.kt:44)
at me.ebonjaeger.perworldinventory.serialization.InventorySerializer.serializeInventory(InventorySerializer.kt:43)
at me.ebonjaeger.perworldinventory.serialization.InventorySerializer.serializeAllInventories(InventorySerializer.kt:23)
at me.ebonjaeger.perworldinventory.serialization.PlayerSerializer.serialize(PlayerSerializer.kt:36)
at me.ebonjaeger.perworldinventory.data.FlatFile.savePlayer(FlatFile.kt:43)
at me.ebonjaeger.perworldinventory.data.ProfileManager$addPlayerProfile$1.invoke(ProfileManager.kt:59)
at me.ebonjaeger.perworldinventory.data.ProfileManager$addPlayerProfile$1.invoke(ProfileManager.kt:20)
at me.ebonjaeger.perworldinventory.service.BukkitService$sam$java_lang_Runnable$0.run(BukkitService.kt)
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:53)
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
... 3 more