ActionScript 3.0 :: Error #1502: A Script Has Executed For Longer Than The Default Timeout Period Of 15 Seconds

I have implemented a basic login screen and its working ok except that it's giving me this error and is taking long to execute:
 
Error: Error #1502: A script has executed for longer than the default timeout period of 15 seconds.    at login_screen/Checklogininfo()[login_screen::frame1:34]
 
Script is the following:
 
login_error_lbl.visible = false;login_ok_btn.addEventListener (MouseEvent.CLICK,Checklogininfo);
function Checklogininfo (event:MouseEvent):void{    while ((User_name_txtbox.text != "xx") || (Password_txtbox.text != "y")){      login_error_lbl.visible = true;         /////////////////////////////////////////this part of the "while" is taking very long to execute        User_name_txtbox.text = "";        Password_txtbox.text = "";
}    this.visible = false;}