Trying to create a slider.

Hi, there. I'm creating a photo menu, with a slider.

I have a slideshow and, next to it, a vertical menu with thumbnails of all the photos in the slideshow. As the slideshow plays, the slider slides over the same photo's thumbnail in the menu. When a user mouses over the menu, the slider follows the mouse.

It a lot like the main slideshow on this page: http://www.actioncenter.org/

Everything is working, with one exception. When the slideshow plays, the slider isn't moving from photo to photo. Instead, it's just disappearing from the first photo and reappearing on the second. (I tried adding in motion tweens between each photo of the slideshow, but then if the user mouses over the menu during the tween, the slider gets jumpy.)

I'm using Flash MX 2004 (I know -- I need an update). Anyway, here's the AS I'm using for the slider when it's on the first photo:

onClipEvent (load) {
speed = 3;
}
onClipEvent (enterFrame) {
if (_root._xmouse<890 && _root._xmouse >804 && _root._ymouse<356 && _root._ymouse >45){
endY = _root._ymouse;
_y += (endY-_y)/speed;
}
else {
endY = 75;
_y += (endY-_y)/speed;
}
}


When it's on the second photo, there's this AS:

onClipEvent (load) {
speed = 3;
}
onClipEvent (enterFrame) {
if (_root._xmouse<890 && _root._xmouse >804 && _root._ymouse<356 && _root._ymouse >45){
endY = _root._ymouse;
_y += (endY-_y)/speed;
}
else {
endY = 137;
_y += (endY-_y)/speed;
}
}

Any advice is much appreciated! Thanks!