Windows .exe FML severe error

[Techmanscott]

Can someone help me fix this please?

2013-06-01 20:16:21 [SEVERE] [ForgeModLoader] The ForgeModLoader state engine has become corrupted. Probably, a state was missed by and invalid modification to a base classForgeModLoader depends on. This is a critical error and not recoverable. Investigate any modifications to base classes outside ofForgeModLoader, especially Optifine, to see if there are fixes available.
2013-06-01 20:16:21 [INFO] [STDERR] Exception in thread "Server thread" java.lang.RuntimeException: The ForgeModLoader state engine is invalid
2013-06-01 20:16:21 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.transition(LoadController.java:122)
2013-06-01 20:16:21 [INFO] [STDERR] at cpw.mods.fml.common.Loader.serverStopped(Loader.java:780)
2013-06-01 20:16:21 [INFO] [STDERR] at cpw.mods.fml.common.FMLCommonHandler.handleServerStopped(FMLCommonHandler.java:469)
2013-06-01 20:16:21 [INFO] [STDERR] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:559)
2013-06-01 20:16:21 [INFO] [STDERR] at fy.run(SourceFile:849)

 

[Ashzification]

Do this: http://desk.feed-the-beast.com/index.php?/Knowledgebase/Article/View/9/0/basic-troubleshooting
Then post your entire launcher console log to pastebin.com and link it if you're still having trouble.