project.properties is being updated incorrectly when importing an Existing Android project into Eclipse. This file exists in source control:
# This file is
import your project as you are doing ie
Existing Android code into workspace.
now delete the project.properties. clean and build project.
if existing project has build.xml file import project using this ant build file import option
New-->other-->Java Project from existing Ant file-->
follow further option and you are done
right click your project ---> project properties go to Android Select appropriate API level. Clean and build your project .... Its done now