포지 모드 서버를 열었는데 서버가 열리는거 까지는 성공했지만 서버에 들어가는 순간 오류뜨면서 서버가 닫힙니다.. 왜 그런걸까요.. 도움 부탁드립니다 ㅜㅜ

---- Minecraft Crash Report ----
// Uh... Did I do that?

Time: 19. 7. 6 오후 8:46
Description: Exception ticking world

io.netty.handler.codec.EncoderException: java.lang.NullPointerException
    at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106)
    at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116)
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738)
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:730)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:816)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:723)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:704)
    at io.netty.channel.DefaultChannelPipeline.write(DefaultChannelPipeline.java:1017)
    at io.netty.channel.AbstractChannel.write(AbstractChannel.java:286)
    at io.netty.channel.embedded.EmbeddedChannel.writeOutbound(EmbeddedChannel.java:341)
    at net.minecraftforge.fml.common.network.FMLEmbeddedChannel.generatePacketFrom(FMLEmbeddedChannel.java:72)
    at net.minecraftforge.fml.common.network.internal.FMLNetworkHandler.getEntitySpawningPacket(FMLNetworkHandler.java:134)
    at net.minecraft.entity.EntityTrackerEntry.func_151260_c(EntityTrackerEntry.java:501)
    at net.minecraft.entity.EntityTrackerEntry.func_73117_b(EntityTrackerEntry.java:380)
    at net.minecraft.entity.EntityTracker.func_85172_a(EntityTracker.java:392)
    at net.minecraft.server.management.PlayerChunkMapEntry.func_187272_b(PlayerChunkMapEntry.java:162)
    at net.minecraft.server.management.PlayerChunkMap.func_72693_b(SourceFile:165)
    at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:227)
    at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:756)
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397)
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
    at moe.plushie.armourers_workshop.common.blocks.BlockSkinnable$Seat.writeSpawnData(BlockSkinnable.java:498)
    at net.minecraftforge.fml.common.network.internal.FMLMessage$EntitySpawnMessage.toBytes(FMLMessage.java:213)
    at net.minecraftforge.fml.common.network.internal.FMLRuntimeCodec.encodeInto(FMLRuntimeCodec.java:42)
    at net.minecraftforge.fml.common.network.internal.FMLRuntimeCodec.encodeInto(FMLRuntimeCodec.java:32)
    at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:81)
    at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67)
    at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88)
    ... 22 more

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Server thread
Stacktrace:
    at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106)
    at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116)
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738)
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:730)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:816)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:723)
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:704)
    at io.netty.channel.DefaultChannelPipeline.write(DefaultChannelPipeline.java:1017)
    at io.netty.channel.AbstractChannel.write(AbstractChannel.java:286)
    at io.netty.channel.embedded.EmbeddedChannel.writeOutbound(EmbeddedChannel.java:341)
    at net.minecraftforge.fml.common.network.FMLEmbeddedChannel.generatePacketFrom(FMLEmbeddedChannel.java:72)
    at net.minecraftforge.fml.common.network.internal.FMLNetworkHandler.getEntitySpawningPacket(FMLNetworkHandler.java:134)
    at net.minecraft.entity.EntityTrackerEntry.func_151260_c(EntityTrackerEntry.java:501)
    at net.minecraft.entity.EntityTrackerEntry.func_73117_b(EntityTrackerEntry.java:380)
    at net.minecraft.entity.EntityTracker.func_85172_a(EntityTracker.java:392)
    at net.minecraft.server.management.PlayerChunkMapEntry.func_187272_b(PlayerChunkMapEntry.java:162)
    at net.minecraft.server.management.PlayerChunkMap.func_72693_b(SourceFile:165)
    at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:227)

-- Affected level --
Details:
    Level name: world
    All players: 1 total; [EntityPlayerMP['HoshiMiki'/206, l='world', x=300.50, y=64.15, z=-275.50]]
    Chunk stats: ServerChunkCache: 1066 Drop: 0
    Level seed: -2286362844357135430
    Level generator: ID 00 - default, ver 1. Features enabled: true
    Level generator options: 
    Level spawn location: World: (-84,64,256), Chunk: (at 12,4,0 in -6,16; contains blocks -96,0,256 to -81,255,271), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
    Level time: 1317529 game time, 489706 day time
    Level dimension: 0
    Level storage version: 0x04ABD - Anvil
    Level weather: Rain time: 10135 (now: false), thunder time: 14401 (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:756)
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397)
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
    at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
    Minecraft Version: 1.12.2
    Operating System: Windows 7 (amd64) version 6.1
    Java Version: 1.8.0_211, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 722424760 bytes (688 MB) / 957349888 bytes (913 MB) up to 1895825408 bytes (1808 MB)
    JVM Flags: 0 total; 
    IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
    FML: MCP 9.42 Powered by Forge 14.23.5.2768 7 mods loaded, 7 mods active
    States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored

    | State     | ID                 | Version       | Source                               | Signature                                |
    |:--------- |:------------------ |:------------- |:------------------------------------ |:---------------------------------------- |
    | UCHIJAAAA | minecraft          | 1.12.2        | minecraft.jar                        | None                                     |
    | UCHIJAAAA | mcp                | 9.42          | minecraft.jar                        | None                                     |
    | UCHIJAAAA | FML                | 8.0.99.99     | forge.jar                            | e3c3d50c7c986df74c645c0ac54639741c90a557 |
    | UCHIJAAAA | forge              | 14.23.5.2768  | forge.jar                            | e3c3d50c7c986df74c645c0ac54639741c90a557 |
    | UCHIJAAAA | armourers_workshop | 1.12.2-0.49.0 | Armourers-Workshop-1.12.2-0.49.0.jar | None                                     |
    | UCHIJAAAA | customnpcs         | 1.12          | CustomNPCs_1.12.2(29oct17).jar       | None                                     |
    | UCHIJAAAA | ordinarycoins      | 1.4           | ordinarycoins-1.12.2-1.4.jar         | None                                     |

    Loaded coremods (and transformers): 
    Profiler Position: N/A (disabled)
    Player Count: 1 / 20; [EntityPlayerMP['HoshiMiki'/206, l='world', x=300.50, y=64.15, z=-275.50]]
    Is Modded: Definitely; Server brand changed to 'fml,forge'
    Type: Dedicated Server (map_server.txt)