The app neither installs nor runs on my device. All provisioning profiles are up to date. I've already tried deleting and re-installing them.
The status bar shows that Xcode is building my project, then it says running my project on , then it says "finished running ." Throughout this entire period, the iPod screen stays black. The iPod is being detected in the Organizer and I don't see anything wrong with its configuration. Everything was working perfectly just a couple days ago with Xcode 3.
It doesn't work on the simulator, but it may be important to note that in the simulator it appears to get stuck on "Attaching to " and the simulator refuses to start.
For those reading this in regards to Xcode 4.2, and attempting to run on an earlier device (e.g. iPhone 3G, 2G, iPod 1st gen, etc) I have another solution. New projects created in Xcode 4.2 by default specify 'armv7' in the 'Required Device Capabilities'. You'll need to remove this if wanting to support devices that run armv6 (e.g. the iPhone 3G).
Delete armv7 from the 'Required device capabilities' in yourProjectName-Info.plist
You may also need to change the build settings to compile with armv6 instead of armv7.
This is the default:
Double click on 'Standard (armv7)' to add another, then click the '+' in the popup, and type in 'armv6':
Click done and it should look like this: