Resizing script issue

Hi everybody!
I followed the tutorial on this topic : http://www.kirupa.com/developer/as3/resizing_centering_as3.htm ,but I don’t know why, my script do something a little different, the background takes almost all the screen unless a little white stripe on the top… ?? Why is that?? :h:

You can see that it’s a french version ;p, yes I am not a native speaker… so please excuse my poor english! :bu: