[flexcoders] Alert Box location??

[markflex2007]

Hi.

I use Alert.show to show some text but the Alert box go to coner of the 
screen

I try to use the following code,but I get two alert box

var alert1:Alert = Alert.show("Please input user name");                
         
                    PopUpManager.centerPopUp(alert1);
                    var al1X:Number = 300;
                    var al1Y:Number = 300;
                    alert1.move (al1X, al1Y)                            
Do you have a idea to fix this?

Thanks

Mark