SOAP request not working in PHP

We have wsdl : http://ift.tt/1JbE0cv

IN PHP FILE : i have created a Class with some arrays in it..

class Crmtet {
   public $abc;
   public $abc2;
   public $abc3;
   public $abc4;
 }

$client = new SoapClient(http://ift.tt/1JbE0cv);
$obj = new Crmtet();

$obj->abc= "Test";
$obj->abc2= "Test2";
$obj->abc3= "Test3";
$obj->abc4= "Test4";

$result = $client->CRM_Warehouse_Master_Insert($obj)->CRM_Warehouse_Master_InsertResult;
echo"re".$result;

---

But i am getting below error :

Fatal error: Uncaught SoapFault exception: [soap:Server] Server was unable to process request. ---> Object reference not set to an instance of an object. in E:\EasyPHP-12.1\www\test\inserwarrecrm.php:60 Stack trace: #0 E:\EasyPHP-12.1\www\test\inserwarrecrm.php(60): SoapClient->__call('CRM_Warehouse_M...', Array) #1 E:\EasyPHP-12.1\www\test\inserwarrecrm.php(60): SoapClient->CRM_Warehouse_Master_Insert(Object(Crmtet)) #2 {main} thrown in E:\EasyPHP-12.1\www\test\inserwarrecrm.php on line 60

What is the issue.. can anyone help..??