Minecraft Forge 1.6.2 crashes when adding mods to mod folder (Biomes O'Plenty)

---- Minecraft Crash Report ----

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Time: 8/21/13 12:02 PM

Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: net/minecraft/client/resources/ResourceLocation

at cpw.mods.fml.common.LoadController.transition(LoadController.java:149)

at cpw.mods.fml.common.Loader.loadMods(Loader.java:522)

at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:181)

at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:470)

at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:796)

at net.minecraft.client.main.Main.main(SourceFile:101)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:57)

at net.minecraft.launchwrapper.Launch.main(Launch.java:18)

Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/resources/ResourceLocation

at biomesoplenty.helpers.Localizations.<clinit>(Localizations.java:13)

at biomesoplenty.BiomesOPlenty.preInit(BiomesOPlenty.java:76)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:540)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)

at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)

at com.google.common.eventbus.EventBus.dispatch(EventBus.java:313)

at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)

at com.google.common.eventbus.EventBus.post(EventBus.java:267)

at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:194)

at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:174)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)

at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)

at com.google.common.eventbus.EventBus.dispatch(EventBus.java:313)

at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)

at com.google.common.eventbus.EventBus.post(EventBus.java:267)

at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:105)

at cpw.mods.fml.common.Loader.loadMods(Loader.java:521)

... 10 more

Caused by: java.lang.ClassNotFoundException: net.minecraft.client.resources.ResourceLocation

at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)

at java.lang.ClassLoader.loadClass(ClassLoader.java:306)

at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

... 39 more

Caused by: java.lang.NullPointerException

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

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-- System Details --

Details:

Minecraft Version: 1.6.2

Operating System: Mac OS X (x86_64) version 10.7.5

Java Version: 1.6.0_51, Apple Inc.

Java VM Version: Java HotSpot 64-Bit Server VM (mixed mode), Apple Inc.

Memory: 27601096 bytes (26 MB) / 108969984 bytes (103 MB) up to 1065025536 bytes (1015 MB)

JVM Flags: 1 total; -Xmx1G

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 v8.04 FML v6.2.54.841 Minecraft Forge 9.10.0.841 4 mods loaded, 4 mods active

mcp{8.04} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized

FML{6.2.54.841} [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized

Forge{9.10.0.841} [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized

BiomesOPlenty{0.5.6} [biomes O' Plenty] (Biomes-O-Plenty-0.5.6-1.6.2.jar) Unloaded->Constructed->Errored