I crash everytime i use more than 1 mod

is there any way to fix this?
My friend crashes everytime he uses more then 1 mod.
 

java.lang.VerifyError: Control flow falls through code end
Exception Details:
  Location:
    net/minecraftforge/fml/common/discovery/asm/ASMModParser.toString()Ljava/lang/String; @41: <invalid>
  Reason:
    Error exists in the bytecode
  Bytecode:
    0x0000000: 129a b800 9e12 a02a b400 5cb6 0079 b600
    0x0000010: a412 a52a b400 5eb6 00a8 12aa 2ab4 0068
    0x0000020: b600 79b6 00a4 12ab 2a                 

    at net.minecraftforge.fml.common.discovery.JarDiscoverer.discover(JarDiscoverer.java:69)
    at net.minecraftforge.fml.common.discovery.ContainerType.findMods(ContainerType.java:42)
    at net.minecraftforge.fml.common.discovery.ModCandidate.explore(ModCandidate.java:71)
    at net.minecraftforge.fml.common.discovery.ModDiscoverer.identifyMods(ModDiscoverer.java:134)
    at net.minecraftforge.fml.common.Loader.identifyMods(Loader.java:363)
    at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:488)
    at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:208)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
    at net.minecraft.client.main.Main.main(SourceFile:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Edited August 26, 20214 yr by SleepyClerric