You are not launching SoapClient in WSDL mode, you need to give SoapClient the WSDL file either as a local file or a URL.
I modifed your code, so it works now. Note that "location" is now a variable which is used to form the start of the WSDL URL for the SoapClient
I assume you are using PHP 5.1+
$location = "https://$host:443/iControl/iControlPortal.cgi";
// Create SOAP instance
$args = array('soap_version' => SOAP_1_1,
'location' => $location,
'login' => $login,
'password' => $password);
//note the SoapClient is called with WSDL as a first parameter
$this->_client = new SoapClient($location . '?WSDL=GlobalLB.WideIP', $args);
//get WideIPs from iControl
$wide_ips = $this->_client->get_list();
// List Wide-IP's
var_dump($wide_ips);
//get object status
$status_array=$this->_client->get_object_status($wide_ips);
var_dump($status_array);
Hope this helps.
Sam