I just tried to install forge and it wont work. It got a Black Screen right after i installed it. I even got a fresh .minecraft folder.
Here's The Log:
2013-01-04 16:59:50 [iNFO] [ForgeModLoader] Forge Mod Loader version 4.6.12.511 for Minecraft 1.4.6 loading
2013-01-04 16:59:50 [FINEST] [ForgeModLoader] All core mods are successfully located
2013-01-04 16:59:50 [FINEST] [ForgeModLoader] Discovering coremods
2013-01-04 16:59:50 [FINEST] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/argo-2.25.jar
2013-01-04 16:59:50 [iNFO] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/argo-2.25.jar
2013-01-04 16:59:50 [iNFO] [sTDOUT] Request: GET http://files.minecraftforge.net/fmllibs/argo-2.25.jar
2013-01-04 16:59:50 [iNFO] [sTDOUT] No handler. Piping.
2013-01-04 16:59:51 [iNFO] [sTDOUT] Piping finished, data size: 123642
2013-01-04 16:59:51 [FINEST] [ForgeModLoader] Download complete
2013-01-04 16:59:51 [iNFO] [ForgeModLoader] Download complete
2013-01-04 16:59:51 [FINEST] [ForgeModLoader] Library file argo-2.25.jar was downloaded and verified successfully
2013-01-04 16:59:51 [FINEST] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/guava-12.0.1.jar
2013-01-04 16:59:51 [iNFO] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/guava-12.0.1.jar
2013-01-04 16:59:52 [iNFO] [sTDOUT] Request: GET http://files.minecraftforge.net/fmllibs/guava-12.0.1.jar
2013-01-04 16:59:52 [iNFO] [sTDOUT] No handler. Piping.
2013-01-04 16:59:54 [iNFO] [sTDOUT] Piping finished, data size: 1795932
2013-01-04 16:59:54 [FINEST] [ForgeModLoader] Download complete
2013-01-04 16:59:54 [iNFO] [ForgeModLoader] Download complete
2013-01-04 16:59:54 [FINEST] [ForgeModLoader] Library file guava-12.0.1.jar was downloaded and verified successfully
2013-01-04 16:59:54 [FINEST] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/asm-all-4.0.jar
2013-01-04 16:59:54 [iNFO] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/asm-all-4.0.jar
2013-01-04 16:59:54 [iNFO] [sTDOUT] Request: GET http://files.minecraftforge.net/fmllibs/asm-all-4.0.jar
2013-01-04 16:59:54 [iNFO] [sTDOUT] No handler. Piping.
2013-01-04 16:59:55 [FINEST] [ForgeModLoader] Download complete
2013-01-04 16:59:55 [iNFO] [ForgeModLoader] Download complete
2013-01-04 16:59:55 [FINEST] [ForgeModLoader] Library file asm-all-4.0.jar was downloaded and verified successfully
2013-01-04 16:59:55 [FINEST] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/bcprov-jdk15on-147.jar
2013-01-04 16:59:55 [iNFO] [ForgeModLoader] Downloading file http://files.minecraftforge.net/fmllibs/bcprov-jdk15on-147.jar
2013-01-04 16:59:55 [iNFO] [sTDOUT] Piping finished, data size: 212767
2013-01-04 16:59:55 [iNFO] [sTDOUT] Request: GET http://files.minecraftforge.net/fmllibs/bcprov-jdk15on-147.jar
2013-01-04 16:59:55 [iNFO] [sTDOUT] No handler. Piping.
2013-01-04 16:59:57 [iNFO] [sTDOUT] Piping finished, data size: 1997327
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Download complete
2013-01-04 16:59:58 [iNFO] [ForgeModLoader] Download complete
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Library file bcprov-jdk15on-147.jar was downloaded and verified successfully
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Running coremod plugins
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Running coremod plugin FMLCorePlugin
2013-01-04 16:59:58 [iNFO] [ForgeModLoader] Found valid fingerprint for Minecraft Forge. Certificate fingerprint de4cf8a3f3bc15635810044c39240bf96804ea7d
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Coremod plugin FMLCorePlugin run successfully
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Running coremod plugin FMLForgePlugin
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Coremod plugin FMLForgePlugin run successfully
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Validating minecraft
2013-01-04 16:59:58 [FINEST] [ForgeModLoader] Minecraft validated, launching...
2013-01-04 16:59:59 [iNFO] [sTDERR] Exception in thread "Thread-11" java.lang.RuntimeException: cpw.mods.fml.relauncher.ReflectionHelper$UnableToFindClassException: java.lang.ClassNotFoundException: net.minecraft.Launcher
2013-01-04 16:59:59 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher.relaunchApplet(FMLRelauncher.java:269)
2013-01-04 16:59:59 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher.appletEntry(FMLRelauncher.java:212)
2013-01-04 16:59:59 [iNFO] [sTDERR] at net.minecraft.client.MinecraftApplet.init(MinecraftApplet.java:25)
2013-01-04 16:59:59 [iNFO] [sTDERR] at net.minecraft.Launcher.replace(Launcher.java:136)
2013-01-04 16:59:59 [iNFO] [sTDERR] at net.minecraft.Launcher$1.run(Launcher.java:79)
2013-01-04 16:59:59 [iNFO] [sTDERR] Caused by: cpw.mods.fml.relauncher.ReflectionHelper$UnableToFindClassException: java.lang.ClassNotFoundException: net.minecraft.Launcher
2013-01-04 16:59:59 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.ReflectionHelper.getClass(ReflectionHelper.java:159)
2013-01-04 16:59:59 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.FMLRelauncher.relaunchApplet(FMLRelauncher.java:254)
2013-01-04 16:59:59 [iNFO] [sTDERR] ... 4 more
2013-01-04 16:59:59 [iNFO] [sTDERR] Caused by: java.lang.ClassNotFoundException: net.minecraft.Launcher
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.net.URLClassLoader$1.run(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.net.URLClassLoader$1.run(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.security.AccessController.doPrivileged(Native Method)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.net.URLClassLoader.findClass(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.lang.Class.forName0(Native Method)
2013-01-04 16:59:59 [iNFO] [sTDERR] at java.lang.Class.forName(Unknown Source)
2013-01-04 16:59:59 [iNFO] [sTDERR] at cpw.mods.fml.relauncher.ReflectionHelper.getClass(ReflectionHelper.java:151)
2013-01-04 16:59:59 [iNFO] [sTDERR] ... 5 more