[eliasson]

Prova följande och se om den fungerar bättre:

 function POST ($url, $data, $optional_headers = null) {
   $params = array('http' => array(
         'method' => 'POST',
         'content' => $data
        ));
   if ($optional_headers !== null) {
    $params['http']['header'] = $optional_headers;
   }
   $ctx = stream_context_create($params);
   $fp = @fopen($url, 'rb', false, $ctx);
   if (!$fp) {
    throw new Exception("Problem with $url, $php_errormsg");
   }
   $response = @stream_get_contents($fp);
   if ($response === false) {
    throw new Exception("Problem reading data from $url, $php_errormsg");
   }
   return $response;
 }