I hope someone can help :) It's been troubling me for a while, this one.

I'm running Xcode 4.3.1 with base SDK iOS 5.1.
iPhone version is 4.2.1, an old 3S model I believe.

When hitting Run, Xcode compiles fine and says that it's running my app on the phone. Everything appears like it works, but the app does not launch on the phone. Anyone know what I'm doing wrong here? The app works fine in the simulator.

Also when I try to run the app on a 4S, version 5.1, Xcode says: "Xcode cannot run using the selected device. No provisioned iOS devices are available with a compatible iOS version. Connect an iOS device with a recent enough version of iOS to run your application or choose an iOS simulator as the destination.".