Parameters in function problem

Hello i need build a class with couple of function this is class code :

package classes
    import flash.display.MovieClip;
    import flash.text.TextField;
    import flash.text.TextFormat;
    import fl.controls.Button;

    import mx.controls.Button;
    import mx.controls.buttonBarClasses;
    public class Menu
        public function Menu()

         public function mouseOn(o:Object,btn:Button):void{

My problem is that when i wanna make btn:Button like it`s in description of the class one of function parameters i all the time get error :

1046: Type was not found or was not a compile-time constant: Button.

I have googled it some hours and i dont find anything what can help me ;/ Its any wearder way to make it ? Same happen when i try make
var smthing:Button = new Button();
In function, i have imported all packages i need or bmy not ? :stuck_out_tongue: . Any ideas conceptions ? Plz help