Problema con NuSoap

[utopiko]

Tengo un problema con NuSoap. El problema es que no puedo conectarme a una funcion definida en un WSDL. El Wsdl es http://www.b-kin.com/bcim/Account/Ac...vice.asmx?WSDL, y el codigo con el que me intento conectar al Soap es el siguiente...

Código PHP:

<?php
// Pull in the NuSOAP code
require_once('lib/nusoap.php');
// Create the client instance
error_reporting(0);
$client = new soapclient('http://www.b-kin.com/bcim/Account/AccountService.asmx?WSDL', true);
// Check for an error
$err = $client->getError();
if ($err) {
    // Display the error
    echo '<h2>Constructor error</h2><pre>' . $err . '</pre>';
    // At this point, you know the call that follows will fail
}
 
$proxy= $client->getProxy();
 
//EL USer y el pass no los pongo
$header = '<UserCredentials><userName></userName><passWord></passWord></UserCredentials>'; 
$client->setHeaders($header);
$parametros=array('SearchAccounts.searchRequest.Search.CriteriaCollection.SearchCriteria[0].Attribute' => 'Name','SearchAccounts.searchRequest.Search.CriteriaCollection.SearchCriteria[0].CompareOperator' => 'Contains','SearchAccounts.searchRequest.Search.CriteriaCollection.SearchCriteria[0].Value' => 'c','SearchAccounts.searchRequest.Search.SortDirection' => 'ASC','SearchAccounts.searchRequest.Search.Context' => 'All','SearchAccounts.searchRequest.Search.IsForAllUsers' => 'false','SearchAccounts.searchRequest.PageSize' => '0','SearchAccounts.searchRequest.SortField' => 'Name','SearchAccounts.searchRequest.SortOrder' => 'ASC','SearchAccounts.searchRequest.Columns' => 'Name,Email,AccountId','SearchAccounts.searchRequest.CurrentPageIndex' => 0);
$result = $client->call('SearchAccounts',$parametros);
// Check for a fault
if ($client->fault) {
    echo '<h2>Fault</h2><pre>';
    print_r($result);
    echo '</pre>';
} else {
    // Check for errors
    $err = $client->getError();
    if ($err) {
        // Display the error
        echo '<h2>Error</h2><pre>' . $err . '</pre>';
    } else {
        // Display the result
        echo '<h2>Result</h2><pre>';
       print_r($result);
    echo '</pre>';
    }
}
// Display the request and response
echo '<h2>Request</h2>';
echo '<pre>' . htmlspecialchars($client->request, ENT_QUOTES) . '</pre>';
echo '<h2>Response</h2>';
echo '<pre>' . htmlspecialchars($client->response, ENT_QUOTES) . '</pre>';
// Display the debug messages
echo '<h2>Debug</h2>';
echo '<pre>' . htmlspecialchars($client->debug_str, ENT_QUOTES) . '</pre>';
?>
 

Que es lo que me puede fallar??El error que me da

Código HTML:

Array
(
    [faultcode] => soap:Server
    [faultstring] => Server was unable to process request. ---> Object reference not set to an instance of an object.
    [detail] => 
)
 

Saludos