This uses a timer event and a mask to scroll text.
Download the FLA file
var myTimer:Timer = new Timer(100);
myTimer.addEventListener(TimerEvent.TIMER, scrollText);
myTimer.start();
function scrollText(myEvent:Event):void
{
if (text1_mc.y < -360)
{ text1_mc.y = 20 }
else
{ text1_mc.y -= 1; }
}