Got a problem when joining a server with CrazyMinecraft modpack

I've got this error message on the server

[14:09:13] [Server thread/ERROR] [FML]: SimpleChannelHandlerWrapper exception
java.lang.NullPointerException
        at cpw.mods.fml.common.network.FMLOutboundHandler$OutboundTarget$4.selectNetworks(FMLOutboundHandler.java:109) ~[FMLOutboundHandler$OutboundTarget$4.class:?]
        at cpw.mods.fml.common.network.FMLOutboundHandler.write(FMLOutboundHandler.java:273) ~[FMLOutboundHandler.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.invokeWrite(DefaultChannelHandlerContext.java:644) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.write(DefaultChannelHandlerContext.java:698) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.write(DefaultChannelHandlerContext.java:637) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:115) ~[MessageToMessageEncoder.class:?]
        at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[MessageToMessageCodec.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.invokeWrite(DefaultChannelHandlerContext.java:644) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.write(DefaultChannelHandlerContext.java:698) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.writeAndFlush(DefaultChannelHandlerContext.java:688) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelHandlerContext.writeAndFlush(DefaultChannelHandlerContext.java:717) ~[DefaultChannelHandlerContext.class:?]
        at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:893) ~[DefaultChannelPipeline.class:?]
        at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:239) ~[AbstractChannel.class:?]
        at cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendTo(SimpleNetworkWrapper.java:196) [SimpleNetworkWrapper.class:?]
        at chococraft.common.events.ChocoboPlayerTracker.sendLocalSetupUpdate(ChocoboPlayerTracker.java:91) [ChocoboPlayerTracker.class:?]
        at chococraft.common.events.ChocoboPlayerTracker.onPlayerLogout(ChocoboPlayerTracker.java:73) [ChocoboPlayerTracker.class:?]
        at cpw.mods.fml.common.eventhandler.ASMEventHandler_441_ChocoboPlayerTracker_onPlayerLogout_PlayerLoggedOutEvent.invoke(.dynamic) [?:?]
        at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54) [ASMEventHandler.class:?]
        at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140) [EventBus.class:?]
        at cpw.mods.fml.common.FMLCommonHandler.firePlayerLoggedOut(FMLCommonHandler.java:555) [FMLCommonHandler.class:?]
        at net.minecraft.server.management.ServerConfigurationManager.func_72367_e(ServerConfigurationManager.java:318) [oi.class:?]
        at net.minecraft.network.NetHandlerPlayServer.func_147231_a(NetHandlerPlayServer.java:633) [nh.class:?]
        at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:154) [nc.class:?]
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:659) [MinecraftServer.class:?]
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:334) [lt.class:?]
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547) [MinecraftServer.class:?]
        at fastcraft.u.a(F:289) [fastcraft.jar:?]
        at fastcraft.H.aq(F:36) [fastcraft.jar:?]
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:396) [MinecraftServer.class:?]
        at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685) [li.class:?]

please any help