Flash as2 Someone check my code for custom mouse cursor please? Thanks!

programming flash
1

I was instructed to start creating Actionscript Files for game development. Especially if your doing complex RPG style games. Well, for some reason this code is not working in my Actionscript File. It works fine on the main timeline or even on the object itself. I made a cursor and have it set to export to actionscript. Name and ID mainCursor. What am I missing?

class mainCursor extends MovieClip
{
    function onEnterFrame()
    {
        Mouse.hide();
        _root.mainCursor._x = _root._xmouse;
        _root.mainCursor._y = _root._ymouse;
    }
}