Hi I'm having a issue runing my server version of my mod here is the error log

 

---- Minecraft Crash Report ----
// This doesn't make any sense!

Time: 4/8/13 3:07 PM
Description: Exception in server tick loop

java.lang.NoClassDefFoundError: net/minecraft/client/renderer/entity/Render
at mods.GamersMods.Common.mod_DemogorgonMagica.<clinit>(mod_DemogorgonMagica.java:32)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:446)
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.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:165)
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.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:98)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:502)
at cpw.mods.fml.server.FMLServerHandler.beginServerLoading(FMLServerHandler.java:85)
at cpw.mods.fml.common.FMLCommonHandler.onServerStart(FMLCommonHandler.java:352)
at net.minecraft.server.dedicated.DedicatedServer.startServer(DedicatedServer.java:69)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:429)
at net.minecraft.server.ThreadMinecraftServer.run(ThreadMinecraftServer.java:16)
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.renderer.entity.Render
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:211)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 30 more
Caused by: java.lang.RuntimeException: Attempted to load class net/minecraft/client/renderer/entity/Render for invalid side SERVER
at cpw.mods.fml.common.asm.transformers.SideTransformer.transform(SideTransformer.java:50)
at cpw.mods.fml.relauncher.RelaunchClassLoader.runTransformers(RelaunchClassLoader.java:292)
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:199)
... 32 more


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

-- System Details --
Details:
Minecraft Version: 1.5.1
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_07, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 1041828544 bytes (993 MB) / 1056309248 bytes (1007 MB) up to 1056309248 bytes (1007 MB)
JVM Flags: 3 total; -Xincgc -Xmx1024M -Xms1024M
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: 0, tallocated: 0
FML: MCP v7.44 FML v5.1.10.621 Minecraft Forge 7.7.1.621 4 mods loaded, 4 mods active
mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML [Forge Mod Loader] (coremods) Unloaded->Constructed
Forge [Minecraft Forge] (coremods) Unloaded->Constructed
DemogorgonMagica [DemogorgonMagica] (bin) Unloaded
Profiler Position: N/A (disabled)
Is Modded: Definitely; Server brand changed to 'fml'
Type: Dedicated Server (map_server.txt)

or use if(FMLCommonHandler.instance().getEffectiveSide().isClient()){

//stuff

}