Building an iPhone project results in:
Failed to launch simulated application: SpringBoard failed to launch application with error: 7
Springboard is the app that launches apps. It's the home screen of the iPhone. I had tons of problems when I tried to get my app running on the phone -- turns out that I had an older version of the SDK that was incompatible with the version of the OS my phone had. Reinstalling the latest SDK did the trick.
Also, have heard that clearing the XCode cache sometimes helps (didn't for me) -- XCode menu->Clear cache...