Unity 4.2.2 to Android (SDK 22.3 API 19) fails when trying to install on emulator

I am a newbie to Unity and Android development. I get the following error when I try to run my project on my emulator. I ran the emulator on eclipse and then I used Build & Run on Unity, It indicates that it tries to install the APK to emulator but it fails with the following console output

installation failed with the following output: pkg: /data/local/tmp/package.apk

Error building player: Unity exception: Unable to install APK! Installation failed. See the Console for details.

Thank you.