How to echo a Flash variable in Php

Okays.Let me start off by saying,"i am a noob".With that said,just ignore my poor explanation.I ve' been struggling to figure out what it is that is missing in my incoherent AS2 codes. What i am trying to achieve is very simple yet,confusing as i am still very new to several statements in AS2. My code below is accepting input from user(s).Then sends entered input to a Php file...which in-turns prints the entry in a new window.(some kinda test i choose to do).

AS 2 code --->

stop();

      submit_btn.onRelease = function() {

    if (Age_txt.text != '') {

var send_lv:LoadVars = new LoadVars();

var receive_lv:LoadVars = new LoadVars();

   send_lv.numby =Age_txt.text;

  send_lv.sendAndLoad("goto.php", receive_lv, "POST");

     getURL("goto.php", "_blank", "POST");

    } else {

   error_box.text = 'Fill fields correctly';

  }

};

Php goes like -->  <goto.php>

<?PHP

$catch=$_POST['numby'];

$hollaback='your fake age is $catch';

if($_POST[numby]) {

echo $hollaback ;

  }else {

         echo "you have entered nothing"; } 

?>

PS: The getURL() in my line 8 is just my way of forcing 'goto.php' to tell me what it caught in it's memory. I do not wish to send the msg back to flash via error_box.

                                                                                                          THANKS ALOT PEOPLES!