In file action.addgroup.php, the paths for up,down icons are hardcoded, which
fails if admin dir is renamed.
Paths should include segments for:
$gCms->config['admin_dir']
get_preference(get_userid(), 'admintheme', 'default')

While you're there, would be nice to provide $addttext with 'title=....' and
maybe 'alt=...' too