I try to acess variable named <str> from my php file in as3

1

hello every one

i try to acess a variable named <str> resides in php file from my as3 file

bt i got this error

Error: Error #2101: The String passed to URLVariables.decode() must be a URL-encoded query string containing name/value pairs.
at Error$/throwError()
at flash.net::URLVariables/decode()
at flash.net::URLVariables()
at flash.net::URLLoader/onComplete()

here is my as code

package
{
import flash.display.MovieClip;
import flash.net.URLLoader;
import flash.net.URLRequest;
import flash.net.URLVariables;
import flash.net.URLLoaderDataFormat;
import flash.net.URLRequestMethod;
import flash.net.URLVariables;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.net.navigateToURL;

public class var_AS3_to_PHP extends MovieClip
{    
    var varSend:URLRequest = new URLRequest("http://admin/edudus_beta/NON_USE/xml_data.php");
    var varLoader:URLLoader = new URLLoader();    
    var variables:URLVariables =  new URLVariables();
    
    public function var_AS3_to_PHP():void
    {    
        varSend.method = URLRequestMethod.POST;    
        varSend.data = variables;
        varLoader.dataFormat = URLLoaderDataFormat.VARIABLES;
        
         go_btn.addEventListener(MouseEvent.CLICK, passVar);            
    }    
    private function passVar(ev:MouseEvent):void
    {                    
        variables.var1 = firstName.text;
        variables.var2 = lastName.text;
        varLoader.load(varSend);            
        
        varLoader.addEventListener(Event.COMPLETE,data_Fetched);
    }
    
    function data_Fetched(e:Event):void
    {            
        var phpvar = e.target.data;
        trace(phpvar);
    }
}

}

and here is my php code i want to acesss variable <str> from as3

<?php
$VAR1 = $_POST[var1];
$VAR2 = $_POST[var2];
echo $str = “edudus”.$VAR1;
$str2 = “mkinfo”.$VAR2;
?>

plz help me,