Collision with an object replacing the mouse

[rynoe]

Clips are always squares for hitTest objects so you kinda have to make 3 separate walls unless you wanna use some of the fancier hitTest class files out there.
I'm not sure of the need for your objects to be class files in the library either. If you can, you should consider just drawing the object and convert to symbols. It would make the code rather simple:

import flash.events.MouseEvent;
import flash.events.Event;

ball.addEventListener(MouseEvent.MOUSE_DOWN, startDragging);
ball.addEventListener(MouseEvent.MOUSE_UP, stopDragging);
ball.addEventListener(Event.ENTER_FRAME, hitWalls);

function hitWalls(e:Event):void{
    if(e.currentTarget.hitTestObject(wall1)||e.currentTarget.hitTestObject(wall2)||e.currentTarget.hitTestObject(wall3)){
        e.currentTarget.stopDrag();
        e.currentTarget.x=28;
        e.currentTarget.y = 303;
    }
}
function stopDragging(m:MouseEvent):void{
    m.currentTarget.stopDrag();
}
function startDragging(m:MouseEvent):void{
    m.currentTarget.startDrag();
}