[1.6.4] Server crash when adding mods

Hey, I just started a Forge 1.6.4 server and it works fine without mods!

But I added a 1.6.4 TooManyItems mod to the server and it suddenly crashes!

This is the crash that I am getting! Please help! 

_{---- Minecraft Crash Report ----}

_{// This is a token for 1 free hug. Redeem at your nearest Mojangsta: [~~HUG~~]}

_{Time: 27-8-15 23:43}

_{Description: Exception in server tick loop}

_{java.lang.NoClassDefFoundError: net/minecraft/client/entity/EntityClientPlayerMP}

_{at TMIForgeContainer.tickStart(TMIForgeContainer.java:84)}

_{at cpw.mods.fml.common.SingleIntervalHandler.tickStart(SingleIntervalHandler.java:28)}

_{at cpw.mods.fml.common.FMLCommonHandler.tickStart(FMLCommonHandler.java:122)}

_{at cpw.mods.fml.common.FMLCommonHandler.onPreWorldTick(FMLCommonHandler.java:295)}

_{at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:652)}

_{at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:276)}

_{at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:587)}

_{at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:484)}

_{at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:583)}

_{Caused by: java.lang.ClassNotFoundException: net.minecraft.client.entity.EntityClientPlayerMP}

_{at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:186)}

_{at java.lang.ClassLoader.loadClass(Unknown Source)}

_{at java.lang.ClassLoader.loadClass(Unknown Source)}

_{... 9 more}

_{Caused by: java.lang.NullPointerException}

_{at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:178)}

_{... 11 more}

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

_{---------------------------------------------------------------------------------------}

_{-- System Details --}

_Details:

_{Minecraft Version: 1.6.4}

_{Operating System: Windows 8 (amd64) version 6.2}

_{Java Version: 1.8.0_51, Oracle Corporation}

_{Java VM Version: Java HotSpot 64-Bit Server VM (mixed mode), Oracle Corporation}

_{Memory: 43726960 bytes (41 MB) / 221249536 bytes (211 MB) up to 941621248 bytes (898 MB)}

_{JVM Flags: 0 total;}

_{AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used}

_{Suspicious classes: FML and Forge are installed}

_{IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63}

_{FML: MCP v8.11 FML v6.4.50.1,345 Minecraft Forge 9.11.1.1345 4 mods loaded, 4 mods active}

_{mcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available}

_{FML{6.4.50.1,345} [Forge Mod Loader] (minecraftforge-universal-1.6.4-9.11.1.1345.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available}

_{Forge{9.11.1.1345} [Minecraft Forge] (minecraftforge-universal-1.6.4-9.11.1.1345.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available}

_{TooManyItems{1.6.4} [TooManyItems] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available}

_{Profiler Position: N/A (disabled)}

_{Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used}

_{Player Count: 0 / 20; []}

_{Is Modded: Definitely; Server brand changed to 'fml,forge'}

_{Type: Dedicated Server (map_server.txt)}