use warnings;
use Net::INET6Glue::INET_is_INET6;
require RPC::XML;
require McClient;

my $port = 8011;
my @arr = @ARGV;
my $host = "::1";

my $cli = RPC::XML::Client->new("http://[$host]:$port/RPC2");
my $cli_client = RPC::XML::request->new('AnaXmlRpcHandler.execute', ,R
+PC::XML::array->new(map {RPC::XML::string->new($_)} @arr));
[download]

Now the error is different:

Can't locate object method "value" via package "RPC::XML::Client::request: HTTP server error: Can't connect to ::1:localhost:80 (sock_info: Bad service '80')" (perhaps you forgot to load "RPC::XML::Client::request: HTTP server error: Can't connect to ::1:localhost:80 (sock_info: Bad service '80')"?)

It may be that localhost is either misconfigured, or the url is wrong. Now you'll need to do some error checking. I put a test script together to get you started.

#!/usr/bin/perl

use strict;
use warnings;
use Net::INET6Glue;
require RPC::XML;
require RPC::XML::Client;

my $server_url = 'http://test.xmlrpc.wordtracker.com';

my $cli = RPC::XML::Client->new($server_url);
my $res = $cli->send_request( 'ping', 'guest' );
if ( ${$res} == 1 ) {
    print "Successfully pinged guest account", "\n";
    exit 0;
}
else {
    print "There were problems...\n";
    exit 0;
}
[download]

Experiment with it. If you continue to have problems, post again.

I'm not sure how the code above is relevant, as its doesnt use an IPv6 address/host. I'm able to send XML-RPC requests when connecting to an IPv4 address, as following :

my $host = "localhost";
my $port = 8011;
my $cli = RPC::XML::Client->new("http://$host:$port/RPC2");
my $cli_client = RPC::XML::request->new('AnaXmlRpcHandler.execute', ,R
+PC::XML::array->new(map {RPC::XML::string->new($_)} @arr));
[download]

Have you been able to send XML-RPC requests to an ipv6 addresss?