Minecraft fml crashes on startup?

here is the error code:
at net.minecraft.client.Minecraft.func_9999…
at net.minecraft.client.main.Main.main(Sour…
at sun.reflect.NativeMethodAccessorImpl.inv… Method)
at sun.reflect.NativeMethodAccessorImpl.inv…
at sun.reflect.DelegatingMethodAccessorImpl…
at java.lang.reflect.Method.invoke(Method.j…
at net.minecraft.launchwrapper.Launch.launc…
at net.minecraft.launchwrapper.Launch.main(…

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