New Blog Defaults doesn't display its admin page in WordPress 3.1. You can fix it in cets_blog_defaults.php, function add_siteadmin_page(), by replacing its body with this:
add_options_page('New Blog Defaults',
'New Blog Defaults',
'manage_network_options',
'cets_blog_defaults_management_page',
array(&$this,
'cets_blog_defaults_management_page'));
instead of the call to "add_submenu_page".