Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world
    at exnihilo.blocks.tileentities.TileEntityBarrel.func_145841_b(TileEntityBarrel.java:890)
    at exnihilo.blocks.tileentities.TileEntityBarrel.func_145844_m(TileEntityBarrel.java:899)
    at net.minecraft.server.management.PlayerManager$PlayerInstance.func_151252_a(PlayerManager.java:591)
    at net.minecraft.server.management.PlayerManager$PlayerInstance.func_73254_a(PlayerManager.java:533)
    at net.minecraft.server.management.PlayerManager.func_72693_b(PlayerManager.java:67)
    at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:185)
    at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:625)
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:334)
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)


A detailed walkthrough of the error, its code path and all known details is as follows:
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-- Head --
Stacktrace:
    at exnihilo.blocks.tileentities.TileEntityBarrel.func_145841_b(TileEntityBarrel.java:890)
    at exnihilo.blocks.tileentities.TileEntityBarrel.func_145844_m(TileEntityBarrel.java:899)
    at net.minecraft.server.management.PlayerManager$PlayerInstance.func_151252_a(PlayerManager.java:591)
    at net.minecraft.server.management.PlayerManager$PlayerInstance.func_73254_a(PlayerManager.java:533)
    at net.minecraft.server.management.PlayerManager.func_72693_b(PlayerManager.java:67)
    at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:185)

-- Affected level --
Details:
    Level name: world
    All players: 2 total; -snip-
    Chunk stats: ServerChunkCache: 2301 Drop: 0
    Level seed: -2882348811973602195
    Level generator: ID 00 - default, ver 1. Features enabled: true
    Level generator options: 
    Level spawn location: World: (196,64,256), Chunk: (at 4,4,0 in 12,16; contains blocks 192,0,256 to 207,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
    Level time: 18135522 game time, 18431286 day time
    Level dimension: 0
    Level storage version: 0x04ABD - Anvil
    Level weather: Rain time: 40608 (now: false), thunder time: 1101 (now: false)
    Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
    at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:625)
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:334)
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)