Android SDK is not your target Android version. Target Android version 19 is the API level for android Kitkat.So in you SDK manager check if you have Android 4.4.2(API 19) installed. If you want your target API version to be different then change it in ANdroidManifest.xml
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="18" />
Edit these lines. Here android:targetSdkVersion
is your Android version that you are targeting.