PopUpManager component problem

programming flash
1

Hi kirupa people, I cannot use the PopUpManager class.

import mx.managers.PopUpManager
import mx.containers.Window
win = PopUpManager.createPopUp(_root, Window, true, {closeButton:true});
lo = new Object();
lo.click = function(){
    win.deletePopUp();
}
win.addEventListener("click", lo);

I copied this code from the flash help but I get

**Error** Scene=Scene 1, layer=Layer 1, frame=1:Line 3: Type mismatch.
     win = PopUpManager.createPopUp(_root, Window, true, {closeButton:true});
Total ActionScript Errors: 1   Reported Errors: 1

Note: I have window component in my library.

Any idea?