I get this error whenever I login to WordPress except when I use Firefox.
Opera, IE and even Mozilla fail to log in any user, be it administrator, author or contributor. Yet Firefox shows no problems. I'm not sure if it's a problem with my server. I ported a working setup from the web to a local server to develop WP and had to remove permalink URL rewriting because I couldn't get .htaccess files recognized on my server. Anyone seen this before or decipher what it means:
Warning: array_filter(): The second argument, 'stdClass::is_role', should be a valid callback in /var/www/wordpress/wp-includes/capabilities.php on line 162