Trying to "create_website" via API, keep getting "too many values to unpack"

Trying to create a website with following code

    $sitevars = new xmlrpcmsg("create_website", array(
            new xmlrpcval($session_id, "string"),
            new xmlrpcval($app_site_name, "string"),
            new xmlrpcval(APP_BASEIP, "string"),
            new xmlrpcval(false, "boolean"),
            new xmlrpcval(array(
                $clientdomain)),
            new xmlrpcval(array(
                $app_site_name,
                "/")),  
          )
        );

Also tried:

$sitevars = new xmlrpcmsg("create_website", array(
            new xmlrpcval($session_id, "string"),
            new xmlrpcval($app_site_name, "string"),
            new xmlrpcval(APP_BASEIP, "string"),
            new xmlrpcval(false, "boolean"),
            new xmlrpcval(array(
                new xmlrpcval($clientdomain, "string"))
            ),
            new xmlrpcval(array(
                new xmlrpcval($app_site_name, "string"),
                new xmlrpcval("/", "string"))
            ),


          )
        );

Both give me a "too many values to unpack" error:

xmlrpcresp Object
(
    [val] => 0
    [valtyp] => 
    [errno] => 1
    [errstr] => :too many values to unpack
    [payload] => 
    [hdrs] => Array
        (
            [date] => Fri, 19 Dec 2014 17:11:49 GMT
            [server] => Apache
            [vary] => Cookie
            [content-length] => 317
            [content-type] => text/xml
        )

    [_cookies] => Array
        (
        )

    [content_type] => text/xml
    [raw_data] => HTTP/1.1 200 OK
Date: Fri, 19 Dec 2014 17:11:49 GMT
Server: Apache
Vary: Cookie
Content-Length: 317
Content-Type: text/xml

faultCode
1

faultString
<type 'exceptions.ValueError'>:too many values to unpack

... Is there something I'm missing? Thanks!

EDIT: Here is a dump of the object I create (obfuscated):

xmlrpcmsg Object
(
    [payload] => 
    [methodname] => create_website
    [params] => Array
        (
            [0] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [string] => 94dac30xxxxxxxxc5f94de6cf778
                        )

                    [mytype] => 1
                    [_php_class] => 
                )

            [1] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [string] => appname
                        )

                    [mytype] => 1
                    [_php_class] => 
                )

            [2] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [string] => 75.126.x.x
                        )

                    [mytype] => 1
                    [_php_class] => 
                )

            [3] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [boolean] => 
                        )

                    [mytype] => 1
                    [_php_class] => 
                )

            [4] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [string] => Array
                                (
                                    [0] => dommainname.net
                                )

                        )

                    [mytype] => 1
                    [_php_class] => 
                )

            [5] => xmlrpcval Object
                (
                    [me] => Array
                        (
                            [string] => Array
                                (
                                    [0] => appname
                                    [1] => /
                                )

                        )

                    [mytype] => 1
                    [_php_class] => 
                )

        )

    [debug] => 0
    [content_type] => text/xml
)