Got a similar error.
Fatal error: require_once() [function.require]: Failed opening required ‘/home/vaulty/public_html/wp-load.php’ (include_path=’.:/usr/local/php53/pear’) in /home/vaulty/public_html/wp-admin/admin.php on line 30
Restored from backup and then tried to update to the latest version again. Crashed the site again. Something’s wrong with the latest version of this plugin.
I’ve restored to a backup that has version 2.1.2 and now I get the old Cache directories, /home/vaulty/public_html/wp-content/plugins/all-in-one-event-calendar/cache//home/vaulty/public_html/wp-content/ai1ec_static/, are not writable. Your calendar will perform more slowly until you make this directory writable by the web server.
