no, _alpha is a built-in property of a movie clip, actionscript/flash is different from any other language i can think of.
Im also working with the stage and the items on the stage, and where they go, and what to do, its confusing. If i wanted a certain movieclip to move to lets say 400x, 300y on the stage i would go into the actions for that object and put something like this. The _x and _y properties also begin with _, as well as _xscale, and _yscale, etc.
onClipEvent(enterFrame){
this._x = 400;
this._y = 300;
}