Buttons wont work

okay, im using a menu slider i got off flash kit. it was created in flash mx, im using flash mx2004. the slider works, ie the slider slides lol, but when i want the frame to change upon clicking the button, it wont. here is the code of the button:

on (rollOver) {
// slider - Movie Clip’s Instance Name. button_1 - Button’s Instance Name.
slider.xMove = button_1._x;


the rollover of that button works, not the release.
heres the code of the frame the slider is in:
easeSpeed = 5;
//slider_mc is your Movie Clip’s name, not the Instance Name.
slider_mc.onEnterFrame = function() {
this._x += (xMove1-this._x)/easeSpeed;
button_1.onPress = function() {
xMove = button_1._x;
button_2.onPress = function() {
xMove = button_2._x;
button_3.onPress = function() {
xMove = button_3._x;
button_4.onPress = function() {
xMove = button_4._x;

why wont this work. thanks.