I moved my Android project to a laptop and now I get this when I hit Debug. Sounds like this is a bug? This shouldn\'t happen via Eclipse as far as I know.
I got the same problem and fixed it by just wiping the user data on the emulator. My guess is that the emulator keeps the project installed unless you wipe the data, so if your new project doesn't match some internal parameters it doesn't like it and won't reinstall it.