Sussed it...
enterButton_mc.addEventListener(MouseEvent.CLICK, enterButton);
function enterButton(e:MouseEvent):void
{
TweenLite.to(enterButton_mc, 1, {alpha:0});
TweenLite.to(hand_mc, 1, {alpha:0});
TweenLite.to(introLogo_mc, 3, {scaleX:6, scaleY:6, alpha:1});
OverwriteManager.init(2);
TweenLite.to(introLogo_mc, 1, {alpha:0, delay:1, onComplete:nextFrame});
}