Naming questions

1

i’ve this function


function change(i, k) {
 setProperty(k, _visible, false);
 setProperty(i, _visible, true);
 setProperty(i, _alpha, 10);
 i.onEnterFrame = function(){
  trace(boe);
  this._alpha = alpha;
  alpha +=2;
  if(alpha > 99){
   delete this.onEnterFrame;
  }
 }
 _root.clicked = i;
}

but it won’t execute the i.onEnterFrame. the var i I gave when i call the function is “_root.menu.sub0” (WITH quotes);
why doesn’t my function work?