With the latest version of the plugin, going to the Ad Server Settings (/wp-admin/edit.php?post_type=ad-layer&page=ad_layers_ad_server_settings) page in wp-admin throws the following exception, resulting in a fatal error:
PHP Fatal error: Uncaught exception 'FM_Submenu_Not_Initialized_Exception' with message 'The Fieldmanger context for this submenu was not initialized'
This renders the plugin no longer fully configurable via the wp-admin UI.