AS2 Load Vars SendAndLoad返回undefined

I have an old site developed in actionscript2 where I have to get some information from database in php.

I have tried to use SendAndLoad method but always returns undefined.

This my flash script:

news = new LoadVars();
news.onLoad = function(success){
      if(success){
         trace(this.msg);
      } else {
         trace("Error reading the php page");

      }
   }
 news.sendAndLoad("json/news.php", news, "POST");

and this is news.php (only a test but not works always return undefined msg)

<?php
    echo "login=false&";
    echo "msg=missing data";
?>

How can I solve it?

Thanks

You need 2 LoadsVars. One for sending and one for receiving.

toSend.sendAndLoad(address, toRecieve, 'POST');