Bukkit

What steps will reproduce the problem?
1. Install plugin
2. Have players play on server
3. Error occurred
(that's all I know)

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

What version of the product are you using?
Latest

Do you have an error log of what happened?
Yes

Please provide any additional information below.

29.09 19:56:19 [Server] WARN at java.lang.Thread.run(Thread.java:745)
29.09 19:56:19 [Server] WARN at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557)
29.09 19:56:19 [Server] WARN at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654)
29.09 19:56:19 [Server] WARN at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374)
29.09 19:56:19 [Server] WARN at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:723)
29.09 19:56:19 [Server] WARN at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350)
29.09 19:56:19 [Server] WARN at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.ExplodedBlockManager$2.run(ExplodedBlockManager.java:297)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.ExplodedBlockManager.access$1(ExplodedBlockManager.java:216)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.ExplodedBlockManager.checkReplace(ExplodedBlockManager.java:222)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.CreeperExplosion.checkReplace(CreeperExplosion.java:342)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.CreeperExplosion.replace_one_block(CreeperExplosion.java:167)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.CreeperBlock.replace(CreeperBlock.java:247)
29.09 19:56:19 [Server] WARN at com.nitnelave.CreeperHeal.block.CreeperChest.update(CreeperChest.java:149)
29.09 19:56:19 [Server] WARN java.lang.ClassCastException: org.bukkit.craftbukkit.v1_8_R3.block.CraftBlockState cannot be cast to org.bukkit.inventory.InventoryHolder
29.09 19:56:19 [Server] WARN AIR at -708; 71; 2996
29.09 19:56:19 [Server] WARN org.bukkit.craftbukkit.v1_8_R3.block.CraftBlock
29.09 19:56:19 [Server] WARN ClassCastException when replacing a chest :
29.09 19:56:19 [Server] WARN Error detected, please report the whole message