Recently I upgraded Eclipse along with ADT plugins to Android L priew.
I have the latest Java update as well i.e. Java 8
This seems to be the issue....the 'Automatically Pick Best', picks the 'L' version of API 20 instead of the 4.x version of API 20. In my instance, I am targeting API 19 and apparently that's not compatible with the choice of "API 20: Android L (Preview)".
Sorry, this system won't let me post images yet...