I’ve been doing some iPhone development with XCode recently and had problems using the debugger on the device (not the simulator) and also with taking screenshots.
When installing an application on to the device, the debugger would say:
"Failed to start remote debugserver for MyApp.app"
I search around looking for a solution. In a thread somewhere, someone suggested reinstalling the SDK from scratch. I had first installed the SDK about a year ago when it came out. I then installed several updates over it. For whatever reason, that cause problems.
After reinstalling the latest SDK from Apple website, the debugger worked perfectly! And I was able to take screenshots from the device.