why the position of textfield changed

I have in the asp page the values like screenx=617&screeny=-8.5&text=dsdsdsds&

And I create an new flashpage which only has a textfield(which named as screen) to receive the text from asp page and position it to the place.
myData = new LoadVars();
myData.source = "http://localhost/myweb/cart.asp";
myData.load(myData.source,myData);
myData.onLoad = function(){
_root.screen.text= myData.text;
_root.screen._x = this.screenx;
_root.screen._y = this.screeny;
};

the result of the _y of screen seems the same as the value in asp, but not the _x value!!

Is there something related with the setting of the flashpage which make the result different? Thanks in advance and wait for your reply