23:09:49  [Server thread/ERROR]: Encountered an unexpected exception
23:09:49 java.lang.NullPointerException
23:09:49 at mcp.mobius.betterbarrels.common.blocks.TileEntityBarrel.sendContentSyncPacket(TileEntityBarrel.java:557) ~[TileEntityBarrel.class:?]
23:09:49 at mcp.mobius.betterbarrels.common.blocks.TileEntityBarrel.markDirtyExec(TileEntityBarrel.java:551) ~[TileEntityBarrel.class:?]
23:09:49 at mcp.mobius.betterbarrels.ServerTickHandler.tickServer(ServerTickHandler.java:41) ~[ServerTickHandler.class:?]
23:09:49 at cpw.mods.fml.common.eventhandler.ASMEventHandler_542_ServerTickHandler_tickServer_ServerTickEvent.invoke(.dynamic) ~[?:?]
23:09:49 at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54) ~[ASMEventHandler.class:?]
23:09:49 at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:138) ~[EventBus.class:?]
23:09:49 at cpw.mods.fml.common.FMLCommonHandler.onPreServerTick(FMLCommonHandler.java:260) ~[FMLCommonHandler.class:?]
23:09:49 at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:536) ~[MinecraftServer.class:?]
23:09:49 at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427) [MinecraftServer.class:?]
23:09:49 at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685) [li.class:?]