In the file plugins/eventful/vendors/startup.php, the code is currently shown as:
App::import('File', APP . 'app_model_events.php');
App::import('File', APP . 'app_controller_events.php');
but should be written as:
App::import('File','AppModelEvents',false,array(), APP . 'app_model_events.php');
App::import('File','AppControllerEvents',false,array(), APP . 'app_controller_events.php');
Those files aren't currently working due to this.