Problème Minecraft Mo' Creatures Mod

Bonjour,

J'ai acheté la version beta 1.2 02 de Minecraft la semaine dèrniere. Mon ami m'a alors parlé d'un mod a Minecraft nommé Mo' Creatures mod. J'ai donc voulu l'installer. Au prmier coup d'oeuil je semblais l'avoir fait correctement, mais quand j'ai ouvert Minecraft, le code d'erreur suivant est apparu.

Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem.

If you wish to report this, please copy this entire text and email it to support@mojang.com.
Please include a description of what you did when the error occured.

Mods loaded: 1
ModLoader Beta 1.2_02v4

--- BEGIN ERROR REPORT 9e30d104 --------
Generated 11-02-12 08:00

Minecraft: Minecraft Beta 1.2_02
OS: Windows Vista (x86) version 6.0
Java: 1.6.0_23, Sun Microsystems Inc.
VM: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
LWJGL: 2.4.2
OpenGL: Mobile Intel(R) 4 Series Express Chipset Family version 2.1.0 - Build 8.15.10.2202, Intel

java.lang.VerifyError: Cannot inherit from final class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
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.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at ModLoader.addMod(ModLoader.java:157)
at ModLoader.readFromClassPath(ModLoader.java:662)
at ModLoader.init(ModLoader.java:527)
at ModLoader.AddAllRenderers(ModLoader.java:81)
at oc.<init>(oc.java:55)
at oc.<clinit>(oc.java:8)
at net.minecraft.client.Minecraft.a(SourceFile:253)
at net.minecraft.client.Minecraft.run(SourceFile:606)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT ae1f2c26 ----------