RidleyXD

Hi, I'm a fairly new Tekkit user, and I wanted to start the summer by playing a bit of the newer Tekkit. But for some reason, whenever it gets to the Minecraft window for any modpack, it closes automatically! Can someone help me out? I use a Mac, and downloaded the GalacticCraft, Super Aether, Planesboatscars mod packs. Would they be causing a problem?