Call SOAP demo client with any access control exception (missing soap capability, valid until date expired on the token...)
When the SOAP client requests the WSDL (new SoapClient($serverurl), the server will throw an exception during the WSDL generation. This exception is converted by the server into a SOAPFAULT. Somehow the client does not recognize this format.
It could be an error on the client (maybe a setup) or it could be the server that returned a format not recognized by PHP SOAP Client.