error createWidgets เขียน webservice โดยใช้ CodeIgnite Framework ครับ

Webservice ( Error ที่บรรทัด $id = $this->widgets_model->createWidget($data); )
    function post()
    {
		$data = $this->_post_args;
		try {
			$id = $this->widgets_model->createWidget($data);
			//$id = 3; // test code
			//throw new Exception('Invalid request data', 400); // test code
			//throw new Exception('Widget already exists', 409); // test code
		} catch (Exception $e) {
			// Here the model can throw exceptions like the following:
			// * For invalid input data: new Exception('Invalid request data', 400)
			// * For a conflict when attempting to create, like a resubmit: new Exception('Widget already exists', 409)
			$this->response(array('error' => $e->getMessage()), $e->getCode());
		}


		if ($id) {
			$widget = array('id' => $id, 'name' => $data['name']); // test code
			//$widget = $this->widgets_model->getWidget($id);
			$this->response($widget, 201); // 201 being the HTTP response code
		} else
			$this->response(array('error' => 'Widget could not be created'), 404);
    }