MineCraft crashes after getting an item!?

I recently began on Minecraft, and it was fine when I installed a few mods, first was the TooManyItems, next was the ModLoader and ModLoader_MP, then I got the SDK Gun Mod. When I followed the instructions to the Plane + Vehicles all-in-one mod, it crashes every time I obtain a material, ranging from stone, to paintings. Does anyone know anything which fixes this problem?