Fast forward and reverse movie button

1

I have attached the .fla file(flash8), can anyone help me?, I cant figure out how to keep my scroller from going off screen.

this is the action that was applied to my movie clip controller.

stop();
onEnterFrame = nextFrame;
myButton.onEnterFrame = function() {
this._x = _currentframe + 25;
};
myButton.onPress = function() {
delete this.onEnterFrame;
startDrag(this, false, 65, this._y, 525, this._y);
onEnterFrame = function () {
gotoAndStop(Math.round(myButton._x - 25));
};
};
myButton.onRelease = myButton.onReleaseOutside = function () {
stopDrag();
onEnterFrame = nextFrame;
this.onEnterFrame = function() {
this._x = _currentframe + 25;
};
};