meowxiik

I've started a server, and after ~5 mins of loading up, it showed this: [12:40:44] [Server thread/ERROR]: Encountered an unexpected exception java.lang.NoClassDefFoundError: net/minecraft/client/multiplayer/WorldClient at net.minecraft.profiler.Profiler.func_76320_a(Profiler.java:64) ~[qi.class:?] at net.minecraft.world.World.func_147465_d(World.java:459) ~[ahb.class:?] at net.minecraft.block.BlockDoublePlant.func_149889_c(BlockDoublePlant.java:140) ~[ako.class:?] at net.minecraft.world.gen.feature.WorldGenDoublePlant.func_76484_a(SourceFile:28) ~[arm.class:?] at net.minecraft.world.biome.BiomeGenPlains.func_76728_a(BiomeGenPlains.java:79) ~[aip.class:?] at net.minecraft.world.gen.ChunkProviderGenerate.func_73153_a(ChunkProviderGenerate.java:421) ~[aqz.class:?] at net.minecraft.world.gen.ChunkProviderServer.func_73153_a(ChunkProviderServer.java:279) ~[ms.class:?] at net.minecraft.world.chunk.Chunk.func_76624_a(Chunk.java:1055) ~[apx.class:?] at net.minecraft.world.gen.ChunkProviderServer.originalLoadChunk(ChunkProviderServer.java:190) ~[ms.class:?] at net.minecraft.world.gen.ChunkProviderServer.loadChunk(ChunkProviderServer.java:131) ~[ms.class:?] at net.minecraft.world.gen.ChunkProviderServer.func_73158_c(ChunkProviderServer.java:101) ~[ms.class:?] at net.minecraft.server.MinecraftServer.func_71222_d(MinecraftServer.java:265) ~[MinecraftServer.class:?] at net.minecraft.server.MinecraftServer.func_71247_a(MinecraftServer.java:235) ~[MinecraftServer.class:?] at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:258) ~[lt.class:?] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:387) [MinecraftServer.class:?] at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685) [li.class:?] Caused by: java.lang.ClassNotFoundException: net.minecraft.client.multiplayer.WorldClient at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.11.jar:?] at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_11] at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_11] ... 16 more Caused by: java.lang.RuntimeException: Attempted to load class bjf for invalid side SERVER at cpw.mods.fml.common.asm.transformers.SideTransformer.transform(SideTransformer.java:50) ~[server-1.7.10-1231.jar:?] at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:279) ~[launchwrapper-1.11.jar:?] at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:176) ~[launchwrapper-1.11.jar:?] at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_11] at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_11] ... 16 more I am pretty sure, there is some mod, that is only single player, but I can't figure out, what is that mod.