nuSoap -method '' not defined in service

["blackwater dev" <blackwaterdev@xxxxxxxxx>]

I have the following code but when I hit the page, I get the xml error of
method '' not defined in service.  I don't have a wsdl or anything defined.
Is there more I need to do to get the SOAP service set up?

Thanks!

include("nusoap/nusoap.php");

$server=new soap_server();
$server->register('getColumns');

function getColumns(){

       $search= new carSearch();

       return $search->getSearchColumns();

}
$server->service($HTTP_RAW_POST_DATA);