I am getting this exception while I am trying to call an activity from another one. The complete exception is
android.content.ActivityNotFoundExcept
This exception also occurs if you include a library in your app and if the library is calling an activity defined in the library project. In this case we need to merge library's manifest with calling app's manifest.
With ADT version 20, we can do this by adding the below statement in project.properties of calling app.
manifestmerger.enabled=true