(Sorry for two reports in one day...)
Installed Minecraft Forge + Project: RED (Latest stable version) + CodeChickenCore and, on launch, the game crashes with the following crash report:
---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 4/8/14 2:05 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: mrtjp/projectred/transmission/PowerWire_100v
at cpw.mods.fml.common.LoadController.transition(LoadController.java:156)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:523)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:183)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:473)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:808)
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:131)
at net.minecraft.launchwrapper.Launch.main(Launch.java:27)
Caused by: java.lang.NoClassDefFoundError: mrtjp/projectred/transmission/PowerWire_100v
at mrtjp.projectred.ProjectRedExpansion$.preInit(ProjectRedExpansion.scala:27)
at mrtjp.projectred.ProjectRedExpansion.preInit(ProjectRedExpansion.scala)
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:545)
at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
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:201)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:181)
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:112)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:522)
... 10 more
Caused by: java.lang.ClassNotFoundException: mrtjp.projectred.transmission.PowerWire_100v
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:186)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 38 more
Caused by: java.lang.NoClassDefFoundError: mrtjp/projectred/transmission/PowerWire
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:178)
... 40 more
Caused by: java.lang.ClassNotFoundException: mrtjp.projectred.transmission.PowerWire
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:97)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 45 more

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

-- System Details --
Details:
Minecraft Version: 1.6.4
Operating System: Mac OS X (x86_64) version 10.9.2
Java Version: 1.6.0_65, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 31785576 bytes (30 MB) / 130060288 bytes (124 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 v8.11 FML v6.4.45.953 Minecraft Forge 9.11.1.953 13 mods loaded, 13 mods active
mcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized
FML{6.4.45.953} [Forge Mod Loader] (minecraftforge-9.11.1.953.jar) Unloaded->Constructed->Pre-initialized
Forge{9.11.1.953} [Minecraft Forge] (minecraftforge-9.11.1.953.jar) Unloaded->Constructed->Pre-initialized
CodeChickenCore{0.9.0.9} [CodeChicken Core] (minecraft.jar) Unloaded->Constructed->Pre-initialized
ForgeMultipart{1.0.0.244} [Forge Multipart] (ForgeMultipart-universal-1.6.4-1.0.0.244.jar) Unloaded->Constructed->Pre-initialized
ProjRed|Core{4.3.5.30} [ProjectRed] (ProjectRedBase-1.6.4-4.3.5.30.jar) Unloaded->Constructed->Pre-initialized
ProjRed|Transportation{4.3.5.30} [ProjectRed-Transportation] (ProjectRedMechanical-BETA-1.6.4-4.3.5.30.jar) Unloaded->Constructed->Pre-initialized
ProjRed|Compatibility{4.3.5.30} [ProjectRed-Compatibility] (ProjectRedCompat-1.6.4-4.3.5.30.jar) Unloaded->Constructed->Pre-initialized
ProjRed|Integration{4.3.7.32} [ProjectRed-Integration] (ProjectRedIntegration-1.6.4-4.3.7.32.jar) Unloaded->Constructed->Errored
ProjRed|Transmission{4.3.7.32} [ProjectRed-Transmission] (ProjectRedIntegration-1.6.4-4.3.7.32.jar) Unloaded->Constructed->Errored
ProjRed|Expansion{4.3.5.30} [ProjectRed-Expansion] (ProjectRedMechanical-BETA-1.6.4-4.3.5.30.jar) Unloaded->Constructed->Errored
McMultipart{1.0.0.244} [Minecraft Multipart Plugin] (ForgeMultipart-universal-1.6.4-1.0.0.244.jar) Unloaded->Constructed->Pre-initialized
ForgeMicroblock{1.0.0.244} [Forge Microblocks] (ForgeMultipart-universal-1.6.4-1.0.0.244.jar) Unloaded->Constructed->Pre-initialized

See my response on #399 (comment)

The comment I posted after your second crash report

You have 2 versions of ProjectRed at the same time, a big no no.
Update Core,Transportation, Compatibility and Expansion to 4.3.7.32
Your Integration and Transmission modules are already up to date.

Saw it. Sorry, though you meant your first comment. eyes cross DERP.