Custom Post Type content isn’t shown

You need to register you post type with the has_archive argument to get an archive page at /<post_type_slug>/.

Eg.

<?php
add_action('init', 'wpse70469_register');
function wpse70469_register()
{
    $args = array(
        'rewrite' => array("slug" => "vita"),
        'show_in_nav_menus' => true,
        'has_archive' => true, // this makes the archive page work.
    );

    register_post_type('wpse70469_type', $args);
}

You might want read through the arguments for register_post_type. You also don’t need to include query posts like that. WordPress will setup the correct post type and status based on the current request — no need to do that manually.