unable to resolve target 'android'

Unable to resolve target 'android-1' - (Android 1.0) change the "default.properties"
Unable to resolve target 'android-2' - (Android 1.1) change the "default.properties"
Unable to resolve target 'android-3' - install SDK Platform Android 1.5
Unable to resolve target 'android-4' - install SDK Platform Android 1.6
Unable to resolve target 'android-5' - install SDK Platform Android 2.0
Unable to resolve target 'android-6' - install SDK Platform Android 2.0.1
Unable to resolve target 'android-7' - install SDK Platform Android 2.1
Unable to resolve target 'android-8' - install SDK Platform Android 2.2
Unable to resolve target 'android-9' - install SDK Platform Android 2.3
Unable to resolve target 'android-10' - install SDK Platform Android 2.3.3
Unable to resolve target 'android-11' - install SDK Platform Android 3.0
Unable to resolve target 'android-12' - install SDK Platform Android 3.1
Unable to resolve target 'android-13' - install SDK Platform Android 3.2
Unable to resolve target 'android-14' - install SDK Platform Android 4.0
Unable to resolve target 'android-15' - install SDK Platform Android 4.0.3
Unable to resolve target 'android-16' - install SDK Platform Android 4.1
Unable to resolve target 'android-17' - install SDK Platform Android 4.2
Unable to resolve target 'android-18' - install SDK Platform Android 4.3
Unable to resolve target 'android-19' - install SDK Platform Android 4.4
Unable to resolve target 'android-20' - (Android 4.4w) change the "default.properties"
Unable to resolve target 'android-21' - install SDK Platform Android 5.0.1