Running an Android App in Eclipse Causes NullPointerException

Question

I have been following the Android getting started docs and when I try to run the project I get:

!MESSAGE An internal error occurred during: "Launching HelloAndroid".
!STACK 0
java.lang.NullPointerException
        at com.android.ide.eclipse.adt.internal.launch.AndroidLaunchController.launch(Unknown Source)

The application doesn't launch.

Answer 1

Unplugging my Nexus One and restarting Eclipse fixed the problem. Not sure why.

Answer 2

Same here - unplugging a Milestone and restarting Eclipse did the job.