Add the files to your application.
/app/View/Errors/
Follow the installation instructions for the twitterBootstrapHelper
- Twitter Bootstrap Helper - https://github.com/loadsys/twitter-bootstrap-helper
- Twitter Bootstrap Alerts - http://twitter.github.com/bootstrap/components.html#alerts
- Cakephp views: http://book.cakephp.org/2.0/en/views.html