Missing Method in ContentItemsController

You are seeing this error because the action function.file-exists is not defined in controller ContentItemsController

If you want to customize this error message, create app/views/errors/missing_action.thtml.

Fatal: Confirm you have created the ContentItemsController::function.file-exists() in file : app/controllers/content_items_controller.php

<?php
class ContentItemsController extends AppController {
   function function.file-exists() {
   }
}
?>