Getting Authorization error when trying to integrate the vantive in php

Hi i having php site using codeigniter. Now i want to integrate the vantive payment gateway to mysite. I done the installation of php sdk using composer. Now when i run the sample code i got the below error:

Authorization Example
playnation123456110010ecommerceJohn Smith1 Main St.BurlingtonMA01803-3747USVI xxxxxxxxxxxx0000112349
Fatal error: Uncaught exception 'Exception' with message 'Could not resolve host: www.testlitle.com' in C:\xampp\htdocs\vantive\litle\sdk\Communication.php:50 Stack trace: #0 C:\xampp\htdocs\vantive\litle\sdk\LitleXmlMapper.php(35): litle\sdk\Communication::httpRequest('<?xml version="...', Array) #1 C:\xampp\htdocs\vantive\litle\sdk\LitleOnlineRequest.php(732): litle\sdk\LitleXmlMapper->request('<?xml version="...', Array, false) #2 C:\xampp\htdocs\vantive\litle\sdk\LitleOnlineRequest.php(115): litle\sdk\LitleOnlineRequest->processRequest(Array, Array, 'authorization', Array) #3 C:\xampp\htdocs\vantive\test.php(32): litle\sdk\LitleOnlineRequest->authorizationRequest(Array) #4 {main} thrown in C:\xampp\htdocs\vantive\litle\sdk\Communication.php on line 50

Can u please help me for this error ? You can also check the attachment of error screenshot.