listMasterDomains API not error

When I run the below code from my desktop machine I get an error (shown below). When I run it from my server (that is running iWorx) I get absolutely nothing in return. Thoughts?


Desktop Error:

Fatal error: Uncaught SoapFault exception: [WSDL] SOAP-ERROR: Parsing WSDL: Couldn't load from '' : failed to load external entity "" in /Library/WebServer/Documents/__throbber2/xml-test.php:59 Stack trace: #0 /Library/WebServer/Documents/__throbber2/xml-test.php(59): SoapClient->SoapClient('') #1 {main} thrown in /Library/WebServer/Documents/__throbber2/xml-test.php on line 59
$key = '-----BEGIN INTERWORX API KEY-----    MXx...5rPTo=    -----END INTERWORX API KEY-----';
$api_controller = '/nodeworx/siteworx';
$action         = 'listMasterDomains';

$input = array();
$params = array( 'apikey'    => $key,
'ctrl_name' => $api_controller,
'action'    => $action,
'input'     => $input );
$client = new SoapClient( '' );
$result = $client->route( $key, $api_controller, $action, $input );