Movieclip's position changed after loadVars?

Hello, friends, I have in the movieclip where retrieve the movieclip (screen)'s position and the text inside of the movieclip

myData = new LoadVars();
myData.source = "http://localhost/myweb/cart.asp";
myData.onLoad = function(){
_root.screen.text1 = myData.text;
_root.screen._x = this.screenx;
_root.screen._y = this.screeny;
}
myData.load(myData.source, myData);


I have in the cart.asp the position like
screenx=247.25&screeny=7.45&text=helllllllo

but in the flashpage, I can see the its _y value is right, but the _x value is much smaller than that value. Where were I wrong? Thanks in advance.