Some strange shit.

[Wild1145]

[19:43:37] [Server thread/ERROR]: Could not pass event BlockPistonRetractEvent to mcMMO v1.5.02-SNAPSHOT-b${BUILD_NUMBER}
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:305) ~[spigot1.8.jar:git-Spigot-b8f6402-a646500]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot1.8.jar:git-Spigot-b8f6402-a646500]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.BlockPiston.e(BlockPiston.java:72) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.BlockPiston.doPhysics(BlockPiston.java:44) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.World.d(World.java:581) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.BlockDiodeAbstract.h(BlockDiodeAbstract.java:166) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.BlockRepeater.remove(SourceFile:112) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.Chunk.a(Chunk.java:518) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.World.setTypeAndData(World.java:390) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.BlockDiodeAbstract.b(BlockDiodeAbstract.java:41) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.WorldServer.a(WorldServer.java:633) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.WorldServer.doTick(WorldServer.java:238) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:741) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:623) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:526) [spigot1.8.jar:git-Spigot-b8f6402-a646500]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_31]
Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(Unknown Source) ~[?:1.8.0_31]
at java.util.ArrayList.get(Unknown Source) ~[?:1.8.0_31]
at java.util.Collections$UnmodifiableList.get(Unknown Source) ~[?:1.8.0_31]
at com.gmail.nossr50.util.EventUtils.shouldProcessEvent(EventUtils.java:296) ~[?:?]
at com.gmail.nossr50.listeners.BlockListener.onBlockPistonRetract(BlockListener.java:97) ~[?:?]
at sun.reflect.GeneratedMethodAccessor822.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_31]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_31]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301) ~[spigot1.8.jar:git-Spigot-b8f6402-a646500]
... 18 more