Slide Menu when mouse is in certain area

programming flash
1

I am trying to have a menu Slide out from the right, at the bottom of the document, when the (Y) mouse is less than 89, rather than having it scroll out when the mouse is over a big transparent button (because the menu contains buttons itself). This is the code I was using for the menu to slide out when the mouse was over a button with the instance name ‘thumbtrain_menubutton’. If anyone could provide some help it would again be greatly appreciated.

//prototype to get a smooth scrolling animation
Movieclip.prototype.scrollme = function(xPos) {
    /*this moves the movieclip 1/5th of the differece between its 
    current location and where it needs to go
    Because this happens every frame, the difference gets smaller and so 
    does the amount the movieclip is moved - giving us the smooth animation
    */
    this._x -= (this._x-xPos)/10;
};
//initialise a variable
out = false;
//menu mc actions
thumbtrain.onEnterFrame = function() {
    //check a variable
    //this is the same as if(out==true){
    if (out) {
        //call the prototype and provide a target x pos
        this.scrollme(480);
    } else {
        this.scrollme(-65);
    }
};
//the arrow button actions
thumbtrain.thumbtrain_menubutton.onRollOver = function() {
    //check our variable
    if (out) {
        //set variable
        out = false;
        //rotate the mc that contains the arrow button
        thumbtrain.thumbtrain_menubutton._alpha = 80;
    } else {
        //set variable
        out = true;
        //rotate the mc that contains the arrow button
        thumbtrain.thumbtrain_menubutton._alpha = 100;
    }
};
//the bounce prototype
Movieclip.prototype.elasticScale = function(targetS, accel, convert) {
    this.step = this.step * accel + (targetS - this._xscale) * convert 
    this._xscale = this._yscale += this.step
}
//but actions
//use a for loop to reduce repetition of the code
for(i=1;i<6;i++){
    theButton=_root.menu["but"+i];
    //this variable stores what number button it is
    theButton.thisNum=i;
theButton.onEnterFrame=function() {
    //if the mouse is over the but
    if (_root.menu["but"+this.thisNum].overMe) {
        //call the bounce prototype
        this.elasticScale(150, 0.7, 0.3)
    } else {
        this.elasticScale(100, 0.7, 0.3)
    }
}
theButton.onRollOver=function(){
    //set a variable
    thumbtrain.thumbtrain_menubutton["but"+this.thisNum].overMe=true;
    //bring to the front
    thumbtrain.thumbtrain_menubutton["but"+this.thisNum].swapDepths(5000)
}
theButton.onRollOut=function(){
    //set a variable
    thumbtrain.thumbtrain_menubutton["but"+this.thisNum].overMe=false;
}
}