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When i add a mod or try to update existing mods MInecraft crash.When i enter the game after 5 sec a error pops out

---- Minecraft Crash Report ----
// Quite honestly, I wouldn't worry myself about that.

Time: 3/6/13 1:14 AM
Description: Failed to start game

java.lang.IllegalArgumentException: duplicate key: AtomicScience
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:119)
at com.google.common.collect.RegularImmutableMap.<init>(RegularImmutableMap.java:70)
at com.google.common.collect.ImmutableMap$Builder.fromEntryList(ImmutableMap.java:250)
at com.google.common.collect.ImmutableMap$Builder.build(ImmutableMap.java:236)
at com.google.common.collect.Maps.uniqueIndex(Maps.java:638)
at com.google.common.collect.Maps.uniqueIndex(Maps.java:612)
at cpw.mods.fml.common.Loader.identifyMods(Loader.java:337)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:458)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:161)
at net.minecraft.client.Minecraft.a(Minecraft.java:410)
at asq.a(SourceFile:56)
at net.minecraft.client.Minecraft.run(Minecraft.java:744)
at java.lang.Thread.run(Unknown Source)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
Minecraft Version: 1.4.7
Operating System: Windows XP (x86) version 5.1
Java Version: 1.7.0_13, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 362665960 bytes (345 MB) / 518979584 bytes (494 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v7.26 FML v4.7.4.520 Minecraft Forge 6.6.0.497 10 mods loaded, 0 mods active
mcp [Minecraft Coder Pack] (minecraft.jar)
FML [Forge Mod Loader] (coremods)
Forge [Minecraft Forge] (coremods)
AtomicScience [Atomic Science] (minecraft.jar)
BasicComponents [Basic Components] (minecraft.jar)
ICBM|Sentry [ICBM|Sentry] (minecraft.jar)
ICBM|Explosion [ICBM|Explosion] (minecraft.jar)
ICBM|Contraption [ICBM|Contraption] (minecraft.jar)
mod_TooManyItems [mod_TooManyItems] (minecraft.jar)
AtomicScience [Atomic Science] (minecraft.jar)
LWJGL: 2.4.2
OpenGL: ATI Radeon HD 4300/4500 Series GL version 3.3.10750 Compatibility Profile Context, ATI Technologies Inc.
Is Modded: Definitely; Client brand changed to 'forge,fml'
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

That's because you have Forge installed.

Some mod's aren't compatible with it and some require it.