Hooks: admin_footer and admin_print_footer_scripts not working?

As per WordPress Codex its best to register and queue your scripts with the hook dedicated for them, even if you want your script to be added to footer.

So the correct way of doing it will be:

function jupload_scripts() {
    wp_enqueue_script( 'jquery-ui', 'http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/jquery-ui.min.js', array('jquery'), '1.8.6', true );
}
add_action( 'admin_print_scripts', 'jupload_scripts' );