Just attempted to boot up the latest magic world pack and its refusing to load all the other mod packs seem fine:
 
 
 
 
	
	
	
		
				
			
		Code:
	
	--- BEGIN ERROR REPORT db7d3d6d --------
Full report at:
/Users/danpotter/Applications/FTB/Magic_World/minecraft/crash-reports/crash-2013-03-05_22.13.42-client.txt
Please show that file to Mojang, NOT just this screen!
 
Generated 3/5/13 10:13 PM
 
-- System Details --
Details:
    Minecraft Version: 1.4.7
    Operating System: Mac OS X (x86_64) version 10.8.2
    Java Version: 1.6.0_37, Apple Inc.
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
    Memory: 199404512 bytes (190 MB) / 266272768 bytes (253 MB) up to 4277534720 bytes (4079 MB)
    JVM Flags: 6 total; -Xms256M -Xmx4096M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:+AggressiveOpts -XX:PermSize=128m
    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 v7.26a FML v4.7.32.553 Minecraft Forge 6.6.1.524 Feed The Beast Mod Pack 35 mods loaded, 35 mods active
    mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
    FML [Forge Mod Loader] (coremods) Unloaded->Constructed
    Forge [Minecraft Forge] (coremods) Unloaded->Constructed
    CodeChickenCore [CodeChicken Core] (coremods) Unloaded->Constructed
    NotEnoughItems [Not Enough Items] (coremods) Unloaded->Constructed
    CoFHCore [CoFH Core] (CoFHCore.zip) Unloaded->Constructed
    inventorytweaks_forge [Inventory Tweaks (Forge)] (InvTweaks.jar) Unloaded->Errored
    mod_InvTweaks [Inventory Tweaks] (InvTweaks.zip) Unloaded->Constructed
    IronChest [Iron Chest] (IronChest.zip) Unloaded->Constructed
    StevesCarts [Steve's Carts] (StevesCarts.zip) Unloaded->Constructed
    BuildCraft|Core [BuildCraft] (buildcraft.jar) Unloaded->Constructed
    BuildCraft|Energy [BC Energy] (buildcraft.jar) Unloaded->Constructed
    ExtrabiomesXL [ExtrabiomesXL] (extrabiomes.jar) Unloaded->Constructed
    Forestry [Forestry for Minecraft] (forestry.jar) Unloaded->Constructed
    Thaumcraft [Thaumcraft] (Thaumcraft.zip) Unloaded->Constructed
    TwilightForest [The Twilight Forest] (TwilightForest.zip) Unloaded->Constructed
    XReliquary [Xeno's Reliquary] (XReliquary.jar) Unloaded->Constructed
    BuildCraft|Builders [BC Builders] (buildcraft.jar) Unloaded->Constructed
    BuildCraft|Factory [BC Factory] (buildcraft.jar) Unloaded->Constructed
    BuildCraft|Transport [BC Transport] (buildcraft.jar) Unloaded->Constructed
    BuildCraft|Silicon [BC Silicon] (buildcraft.jar) Unloaded->Constructed
    ChickenChunks [ChickenChunks] (chickenchunks.jar) Unloaded->Constructed
    EnderStorage [EnderStorage] (enderstorage.jar) Unloaded->Constructed
    Mystcraft [Mystcraft] (mystcraft.zip) Unloaded->Constructed
    NEIPlugins [NEI Plugins] (neiplugins.jar) Unloaded->Constructed
    ObsidiPlates [Obsidian Pressure Plates] (obsidiplates.zip) Unloaded->Constructed
    ThermalExpansion [Thermal Expansion] (thermalexpansion.zip) Unloaded->Constructed
    OmniTools [OmniTools] (omnitools.zip) Unloaded->Constructed
    Railcraft [Railcraft] (railcraft.jar) Unloaded->Constructed
    mod_ReiMinimap [mod_ReiMinimap] (reiminimap.zip) Unloaded->Constructed
    SecretRoomsMod [The SecretRoomsMod] (secretroomsmod.zip) Unloaded->Constructed
    SoulShards [SoulShards] (soulshards.zip) Unloaded->Constructed
    ThermalExpansion|Factory [Factory] (thermalexpansion.zip) Unloaded->Constructed
    ThermalExpansion|Energy [Energy] (thermalexpansion.zip) Unloaded->Constructed
    ThermalExpansion|Transport [Transport] (thermalexpansion.zip) Unloaded->Constructed
    LWJGL: 2.4.2
    OpenGL: NVIDIA GeForce GT 650M OpenGL Engine GL version 2.1 NVIDIA-8.6.22, NVIDIA Corporation
    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
 
cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: invtweaks.InvTweaksMod
    at cpw.mods.fml.common.LoadController.transition(LoadController.java:130)
    at cpw.mods.fml.common.Loader.loadMods(Loader.java:504)
    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(Thread.java:680)
Caused by: java.lang.ClassNotFoundException: invtweaks.InvTweaksMod
    at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:185)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:57)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:247)
    at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:418)
    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:69)
    at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:153)
    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:69)
    at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:86)
    at cpw.mods.fml.common.Loader.loadMods(Loader.java:494)
    ... 5 more
Caused by: java.lang.UnsupportedClassVersionError: invtweaks/InvTweaksMod : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:174)
    ... 32 more
--- END ERROR REPORT 6b3ba241 ---------- 
				
		