I was making a modpack using magiclauncher, and my game does not load. I was testing the mods individually, and it seams that build craft was the problem. Everything works fine with buildcraft.
I was using Buildcraft version 4.2.1
Here is the list of mods I was using:
Blood Magic
Extra Utilities
Magical Crops
Thaumcraft
WAILA
Applies Energistics
Big Reactors
Buildcraft
ChickenChunks
CodeChickenCore
CoPHCore
EnderIO
EnderStorage
MineFactoryReloaded
NotEnoughItems
PowerCrystalsCore
Tinker's Construct
Thermal Expansion
Translocator
WR-CBE

Here is the logs with Buildcraft:
http://pastebin.com/bQk4mVgu
http://pastebin.com/3k5ZDp25
http://pastebin.com/eiHbuZun
And here with out:
http://pastebin.com/RAZ8PrwD
http://pastebin.com/jyY8ZnXy
http://pastebin.com/VRi2Mi08

And yes, I must have Buildcraft enabled.

BuildCraft 4.2.1 is unsupported. In fact, BuildCraft 4.2.2 is not supported either. Please upgrade to Minecraft 1.7.10.

Also, I believe this kind of issue is related to not having enough RAM and/or PermGen set in your launcher.

:/ ok