Simple fix - basically when I set up eclipse I forgot to set the JAVA_HOME path variable.
The symptoms are this in the console:
[2011-12-12 22:37:05 - RoryHelloWorld] Android Launch![2011-12-12 22:37:05 - RoryHelloWorld] adb is running normally.[2011-12-12 22:37:05 - RoryHelloWorld] Could not find RoryHelloWorld.apk!
The fix is simple. Open up your machines environment variables (in Vista it's Control Panel -> System -> Advanced System Settings -> Environment Variables).
In System Variables add a new variable JAVA_HOME set to where your JDK is installed, e.g.
Then add JAVA_HOME to your Path variable. I added:
%JAVA_HOME%\bin;%PATH%; to the end of mine.
Restart eclipse for the changes to take effect, then the next time you run your app it should work!