MX Slide onEnterFrame question - help please

Welcome to my onEnterFrame nightmare.

OK, so I’m doing this tutorial, which is pretty straightforward, and I’ve got it to work so far. Here’s what it looks like:

on the main timeline:

stop();
_root.slidingObject_mc.onEnterFrame = function() {
if (_root.running && Math.abs(_root.marker_mc._x-this._x)<1) {
this._x = _root.marker_mc._x;
_root.running = false;
} else if (_root.running) {
this._x -= (this._x-_root.marker_mc._x)*.5;
} else {
}
};

on the buttons:
on (press) {
_root.marker_mc._x = 55;
_root.running = true;
}

Here’s what I want to do and I’ve tried to write it a BILLION times and failed -

While running = true, I’d like the timeline of slidingObject_mc to play.

While running = false, it should stop.

HOW DO I SAY THIS IN AS?!! It’s driving me totally NUTS! and, more importantly, once I’ve said it, where to I put it?! On the movie clip I want to play? On the main timeline? Argh!

Please help, I’m sure it’s a very simple question…

Thanks.

-B