[RESOLVED] script slowing flash down

I have an empty shell player which loads swf movies in via the loadmovie function.

I have tested the shell and menu which does the above...all ok so far.

each swf is essentially a unit of work or presentation with scenes used as pages and each scene contains the following code so the user can travel from scene to scene prev or next. However when running it and using the arrow keys....after some time it starts to slow down and I get the message that a script is slowing flash down and do I want to abort the script....could someone point me as to why and a possible solution.

//this is a frame script that uses the two arrow keys

delete keyListener;
var keyListener:Object = new Object();
keyListener.onKeyDown = function() {
var keyCode = Key.getCode();
if (keyCode == 37) {
prevScene();
}
if (keyCode == 39) {
nextScene();
}
};
Key.addListener(keyListener);
stop();

//should I be using something different and even NOT using it as a frame script...could this be why it is slowing flash down.

will use presentation slides for each unit/s; as presenations have key navigation already active.