I tried to go to the "experimental map" in the LondonMap site and the map failed to load. With help from David and Greg, figured out that the problem is an inconsistency in the php versions declared for use in the config files for the site and the version of php actually running. To solve the problem, modify two instances of .htaccess in the LondonMap site (one in the www/ directory, and one in the www/imap/htdocs/ directory) to include: setEnv UVPHP_VERSION 520 where the number (e.g. 520) corresponds to the current version of php running on the server. That can be determined by calling the phpinfo.php file from the root of the site.