Exit Android App with external *actionscript.as* files

Question

Hi, i'm trying to make this code work with a application that got 99% of code driving by external actionscript.as files;
In another app without any external call i mean no actionscript.as files, the code work very fine.
My goal is to shutdown any activity of the app when the user receive a call or something like that;
Many thanks in advance and sorry my english
Scene 1, Layer 'Layer 1', Frame 1, Line 14
1046: Type was not found or was not a compile-time constant: KeyboardEvent.
function handleActivate(event:Event):void
    NativeApplication.nativeApplication.systemIdleMode = SystemIdleMode.KEEP_AWAKE;
function handleDeactivate(event:Event):void
    NativeApplication.nativeApplication.exit();
function handleKeys(event:KeyboardEvent):void        ----- Line 14 -----
    if (event.keyCode == Keyboard.BACK)
        NativeApplication.nativeApplication.exit();
if (Capabilities.cpuArchitecture == "ARM")
    NativeApplication.nativeApplication.addEventListener(Event.ACTIVATE, handleActivate, false, 0, true);
    NativeApplication.nativeApplication.addEventListener(Event.DEACTIVATE, handleDeactivate, false, 0, true);
    NativeApplication.nativeApplication.addEventListener(KeyboardEvent.KEY_DOWN, handleKeys, false, 0, true);

Answer 1

Look Mr. Colin, added the import flash.events.KeyboardEvent; and thats what i got:
Scene 1, Layer 'Layer 1', Frame 1,
Access of undefined property:
NativeApplication
SystemIdleMode
Keyboard
Capabilities
I'm addind this code inside Flash CS6, not via external.as