Building an iPhone project results in:
Failed to launch simulated application: SpringBoard failed to launch application with error: 7
For mine, I got the error when I tried to change the App bundle ID setting in my info.plist file for the sake of running a test. Changing it back cured the problem, but didn't do me any good for the test. Thankfully, the app had loaded in the simulator and I ran it manually for my test.
As far as I can tell, the problem stemmed from having a bundle ID that matched both a specific ID and a wild-card ID. The App IDs I've tried that match only a specific ID/Profile haven't shown a problem.