This is Xcode 4.2, this is still under NDA I think
(only should be submitted to forums of Apple.)
But I think it's somewhere else.
But your "Main Interface" is empty, this is a clean project?
You've created a storyboard-based project. Re-create the project and untick "Use Storyboard" in the project options.
But jnoxx is right, get Xcode 4.0.2. Don't use beta products if you're a n00b.