Mutant Creatures doesn't work :'(

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 12/10/14 2:14 PM
Description: Exception in server tick loop

cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: net/minecraft/client/multiplayer/WorldClient
	at cpw.mods.fml.common.LoadController.transition(LoadController.java:162)
	at cpw.mods.fml.common.Loader.initializeMods(Loader.java:692)
	at cpw.mods.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:97)
	at cpw.mods.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:322)
	at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:279)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:624)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/multiplayer/WorldClient
	at java.lang.Class.getDeclaredConstructors0(Native Method)
	at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
	at java.lang.Class.getConstructor0(Unknown Source)
	at java.lang.Class.newInstance(Unknown Source)
	at cpw.mods.fml.common.network.simpleimpl.SimpleChannelHandlerWrapper.<init>(SimpleChannelHandlerWrapper.java:22)
	at cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper.getHandlerWrapper(SimpleNetworkWrapper.java:129)
	at cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper.addClientHandlerAfter(SimpleNetworkWrapper.java:123)
	at cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper.registerMessage(SimpleNetworkWrapper.java:111)
	at thehippomaster.AnimationAPI.AnimationAPI.init(AnimationAPI.java:27)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:513)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
	at com.google.common.eventbus.EventBus.post(EventBus.java:275)
	at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
	at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
	at com.google.common.eventbus.EventBus.post(EventBus.java:275)
	at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
	at cpw.mods.fml.common.Loader.initializeMods(Loader.java:691)
	... 5 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.multiplayer.WorldClient
	at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:188)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 41 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:51)
	at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:276)
	at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:174)
	... 43 more


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

-- System Details --
Details:
	Minecraft Version: 1.7.10
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_71, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 81403160 bytes (77 MB) / 457179136 bytes (436 MB) up to 2863661056 bytes (2731 MB)
	JVM Flags: 1 total; -Xmx3G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	FML: MCP v9.05 FML v7.10.25.1206 Minecraft Forge 10.13.0.1206 5 mods loaded, 5 mods active
	mcp{9.05} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized
	FML{7.10.25.1206} [Forge Mod Loader] (minecraftserver.jar) Unloaded->Constructed->Pre-initialized->Initialized
	Forge{10.13.0.1206} [Minecraft Forge] (minecraftserver.jar) Unloaded->Constructed->Pre-initialized->Initialized
	AnimationAPI{1.2.3} [AnimationAPI] (AnimationAPI-1.7.10-1.2.3.jar) Unloaded->Constructed->Pre-initialized->Errored
	MutantCreatures{1.4.7} [Mutant Creatures] (MutantCreatures-1.7.10-1.4.7.jar) Unloaded->Constructed->Pre-initialized->Initialized
	Profiler Position: N/A (disabled)
	Player Count: 0 / 10; []
	Is Modded: Definitely; Server brand changed to 'cauldron,craftbukkit,mcpc,fml,forge'
	Type: Dedicated Server (map_server.txt)