connection error localhost php + firebird

I'm having these errors

  Warning: ibase_connect (): Unable to complete network request to host "127.0.0.1". Failed to establish a connection. in C: \ xampp \ htdocs \ panda \ php + fb \ connection.php on line 7

Follow the Firebird connection code in PHP

<?php
class Conexao{
static function conectar(){
$servidor = '127.0.0.1:D:/DB/USER.FDB';
$user = 'SYSDBA';
$passwd = 'masterkey';
$con = ibase_connect($servidor, $user, $passwd);
return $con; 
     }
}
?>