When I press play on the 1.1.2 launcher the work bench will show up for a very short time and Minecraft won't open.

When I press play on the 1.1.2 launcher the work bench will show up for a very short time and Minecraft won't open. I have an iMac which also has Minecraft on it with the same account, I downloaded & installed it the same way as my laptop (the one MC doesn't open on). Attached is a screen shot of what the 'Development Console' after MC's icon closes. Here is a video of what exactly happens ~ http://www.youtube.com/watch?v=Fl1z3zS8I20