Crash when running client

I just made a block and a Item with eclipse and started the game to see if it worked and it crashed :

---- Minecraft Crash Report ----

// I just don't know what went wrong

Time: 13.08.13 11:51

Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: CreeperModder.ExtraMinecraft.client.ClientProxy

at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:75)

at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:519)

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:313)

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.sendEventToModContainer(LoadController.java:194)

at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:174)

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:313)

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:105)

at cpw.mods.fml.common.Loader.loadMods(Loader.java:510)

at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:182)

at net.minecraft.client.Minecraft.startGame(Minecraft.java:470)

at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:796)

at net.minecraft.client.main.Main.main(Main.java:93)

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 net.minecraft.launchwrapper.Launch.launch(Launch.java:57)

at net.minecraft.launchwrapper.Launch.main(Launch.java:18)

Caused by: java.lang.ClassNotFoundException: CreeperModder.ExtraMinecraft.client.ClientProxy

at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:58)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Unknown Source)

at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:58)

... 33 more

Caused by: java.lang.NullPointerException

at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:171)

... 39 more

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

---------------------------------------------------------------------------------------

-- System Details --

Details:

Minecraft Version: 1.6.2

Operating System: Windows XP (x86) version 5.1

Java Version: 1.7.0_13, Oracle Corporation

Java VM Version: Java HotSpot Client VM (mixed mode), Oracle Corporation

Memory: 984492384 bytes (938 MB) / 1067057152 bytes (1017 MB) up to 1067057152 bytes (1017 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 v8.04 FML v6.2.35.804 Minecraft Forge 9.10.0.804 4 mods loaded, 4 mods active

mcp{8.04} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed

FML{6.2.35.804} [Forge Mod Loader] (coremods) Unloaded->Constructed

Forge{9.10.0.804} [Minecraft Forge] (coremods) Unloaded->Constructed

extraminecraftmod{Alpha 1.0} [extraminecraftmod] (bin) Unloaded->Errored

Can someone help me?