Connecting to web service using SOAP & PHP - php

Question

I'm trying to connect to a web service using PHP's soap client which I can successfully do using Visual Studio, pressing F5 and running the page locally which works a treat.
As soon as I upload the exact same file to my apache web host, I keep getting the error: "failed to load external entity".
Here's my code with the credentials and url taken out...
Any ideas?
<?php
header("Access-Control-Allow-Origin: http://example.com");
header("Access-Control-Request-Method: GET,POST");
ini_set('display_errors', true);
ini_set("soap.wsdl_cache_enabled", "0");
error_reporting(E_ALL);
try
{
$soapclient = new SoapClient('http://example.com');
$params = array ('SystemID' => 'testID','Username' => 'test', 'Password' => 'test');
$response = $soapclient->GetEngineerList($params);
print_r($response);
}
catch(SoapFault $e)
{
print_r($e);
}

Answer 1

strings are not read twice and parsed in single quotes
$soapclient = new SoapClient('$url');
try
$soapclient = new SoapClient($url);
also...do you have $url = ''; anywhere?
UPDATE 1
please try using basic auth to get to your wsdl:
$login = 'bert';
$password = 'berts password';
$client = new SoapClient(
'http://' . urlencode($login) . ':' . urlencode($password) . '#www.server.com/path/to/wsdl',
array(
'login' => $login,
'password' => $password
)
);