XML : PHP searching through XML for AS3

I've got this line of code in my AS3 code

   var urlreq = new URLRequest("scriptmareev3.php");      urlreq.method = URLRequestMethod.POST;    

The Php was, originally, on a web server and everything was working. I put it offline in the same folder as my project.

The Php is using an XML file as a database :

  $xml=simplexml_load_file("dataPhp.xml") or die("Error: Cannot read xml");                $rows = count($xml->row)-1;                for ($i = 0; $i <= $rows; $i++)               {                    if ($xml->row[$i]->NOM == $this->port_maree)                  {                      $z0 = $xml->row[$i]->ZO;  ...    

But when I launch my AS3 code, it seems that the php is not returning any variables. I think it doesn't search through my XML.

Is my code correct ?