add_sub_menu page() to be replaced by add_theme_page()

Themes are required to use add_theme_page() in the WordPress Theme Directory. You need:

add_theme_page(
    $this->strings['page_title'],           // Page title
    $this->strings['menu_title'],           // Menu title
    'edit_theme_options',                   // Capability
    $this->menu,                            // Menu slug
    array( &$this, 'install_plugins_page' ) // Callback
);

s

add_theme_page(theme_name.' Settings', theme_name ,'install_themes', 'panel' , 'panel_options');
$theme_page = add_theme_page('Settings', theme_name.' Settings','install_themes', 'panel' , 'panel_options');
add_theme_page(theme_name.' Documentation', 'Documentation','install_themes', 'docs' , 'redirect_docs');
add_theme_page('Support', 'Support','install_themes', 'support' , 'innovative_get_support');