Problems with alpha fading

programming flash
1

I’m having major problems with alpha fading using actionscripting. I can get my objects to fade in and out properly, but when I add more than one object loading them using XML, only one of them will fade in. If I roll over the top MC, the bottom one fades in. But if I roll over the bottom MC the bottom one also fades in again. Also, the works_bg, is an MC inside of an MC so I can control it’s alpha value dynamically. This is the code I am using, where the bold is the alpha fading:

var items = works_xml.firstChild.childNodes; //2d --> 2ditems -->child nodes

for (var i=0; i < items.length; i++) {
    
    var works_info = items*;
    var works_thumb = works_info.attributes.thumbnail;
    var works_text = works_info.attributes.description;
    
    var works_item = mainMenu.attachMovie("works_mc","works"+works_count, 230+works_count);
    works_item._x = 30;
    works_item._y = 125 + (i * works_spacing);
    works_item.works_bg._alpha = 0;
    works_count++;
    
    works_item.descript_txt.text = works_text;
    works_item.thumbnail_mc.loadMovie(works_thumb); //loads thumbnail onto thumbnail_mc
    
    //mouse controls for created movie clips
    works_item.onRollOver = works_item.onDragOver = function(){
        
        **works_item.onEnterFrame = function(){
            if(works_item.works_bg._alpha < 100){
                works_item.works_bg._alpha += 7;
            }
        }
    }
    works_item.onRollOut = works_item.onDragOut = function(){
        works_item.onEnterFrame = function(){
            if(works_item.works_bg._alpha > 0){
                works_item.works_bg._alpha -= 13;
            }**
        }
    }