Tentando testar meu projeto com a execução do Eclipse, mas gera o seguinte erro:

Jul 31, 2013 9:32:50 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Using tweak class name cpw.mods.fml.common.launcher.FMLTweaker
Jul 31, 2013 9:32:50 PM net.minecraft.launchwrapper.LogWrapper log
SEVERE: Unable to launch
java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:99)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:49)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:18)

Ainda

Eu tento clicar na corrida de lugares diferentes, mas ainda não funciona. Alguém sabe por quê?