Omegahack

I don't know where i should post this but. I was trying to make myself a mod and now forge version of minecraft won't work at all no matter what version of forge I use for minecraft. I was following what the person said and this is now what is being posted on my game. Aug 24, 2014 6:17:57 PM net.minecraft.launchwrapper.LogWrapper log INFO: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker Aug 24, 2014 6:17:58 PM net.minecraft.launchwrapper.LogWrapper log INFO: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker Aug 24, 2014 6:17:58 PM net.minecraft.launchwrapper.LogWrapper log INFO: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker 2014-08-24 18:17:58 [iNFO] [ForgeModLoader] Forge Mod Loader version 6.4.49.965 for Minecraft 1.6.4 loading 2014-08-24 18:17:58 [iNFO] [ForgeModLoader] Java is Java HotSpot 64-Bit Server VM, version 1.8.0_20, running on Windows 7:amd64:6.1, installed at C:\Program Files\Java\jre1.8.0_20 2014-08-24 18:17:58 [iNFO] [ForgeModLoader] Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker 2014-08-24 18:17:58 [iNFO] [ForgeModLoader] Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker 2014-08-24 18:17:58 [iNFO] [ForgeModLoader] Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker 2014-08-24 18:17:58 [sEVERE] [ForgeModLoader] Unable to launch java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(Unknown Source) at java.util.ArrayList$Itr.remove(Unknown Source) at net.minecraft.launchwrapper.Launch.launch(Launch.java:114) at net.minecraft.launchwrapper.Launch.main(Launch.java:27) Java HotSpot 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release Is their any way I can fix this? And I also tried redownloading the game as well.