Bukkit

What steps will reproduce the problem?

Install latest Version of plugin on Spigot 1.8

What is the expected output? What do you see instead?

[19:16:20 WARN]: Exception in thread "Craft Scheduler Thread - 623"
[19:16:20 WARN]: org.apache.commons.lang.UnhandledException: Plugin MChest v1.1 generated an exception while executing task 92
    at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: Asynchronous entity world add!
    at org.spigotmc.AsyncCatcher.catchOp(AsyncCatcher.java:14)
    at net.minecraft.server.v1_8_R1.World.b(World.java:2603)
    at net.minecraft.server.v1_8_R1.Chunk.addEntities(Chunk.java:805)
    at org.bukkit.craftbukkit.v1_8_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:40)
    at org.bukkit.craftbukkit.v1_8_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:13)
    at org.bukkit.craftbukkit.v1_8_R1.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:337)
    at org.bukkit.craftbukkit.v1_8_R1.util.AsynchronousExecutor.getSkipQueue(AsynchronousExecutor.java:295)
    at org.bukkit.craftbukkit.v1_8_R1.chunkio.ChunkIOExecutor.syncChunkLoad(ChunkIOExecutor.java:16)
    at net.minecraft.server.v1_8_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:113)
    at net.minecraft.server.v1_8_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:95)
    at org.bukkit.craftbukkit.v1_8_R1.CraftWorld.getChunkAt(CraftWorld.java:124)
    at org.bukkit.craftbukkit.v1_8_R1.CraftWorld.getBlockAt(CraftWorld.java:88)
    at org.bukkit.craftbukkit.v1_8_R1.CraftWorld.getBlockAt(CraftWorld.java:533)
    at org.bukkit.Location.getBlock(Location.java:82)
    at me.foryk.bukkit.magicchest.MagicChestMCWork.fillInv(MagicChestMCWork.java:25)
    at me.foryk.bukkit.magicchest.MagicChestMCWork.fillInvPre(MagicChestMCWork.java:19)
    at me.foryk.bukkit.magicchest.MagicChestMC$1.run(MagicChestMC.java:28)
    at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftTask.run(CraftTask.java:71)
    at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
    ... 3 more

Please provide any additional information below.

Please fix, because the plugin is nice