PierreKamel

If you informed yourself a little, you would know that this mod is for minecraft 1.3.1

I'm 100% sure I have minecraft 1.5.1 because I force updated minecraft and in the main menu it says 1.5.1. And for forge I have the "minecraftforge-universal-1.5.1-7.7.1.662.zip"

Today I downloaded the recommended forge build (universal) for minecraft 1.5.1. I tried to launch it with magic launcher without any other mods and a clean minecraft.jar (1.5.1). Minecraft didn't launch and I received this log: *** MagicMinecraftLauncher 1.0.0 *** java.lang.IncompatibleClassChangeError: Implementing class at java.lang.ClassLoader.defineClass1(Native Method) 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$100(Unknown Source) at java.net.URLClassLoader$1.run(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 magic.launcher.Launcher.main(Unknown Source) It only happens with forge.