Ok guys,
this is a misconfiguration in BitNami and the guys at their forum were awesomely quick replying back. Here are the steps to make it work:
- Go to your installation directory and start manager-windows.exe
- Click "Configure" button
- Click "Open Conf File" button and this opened the httpd.conf file
- Add the line Include "C:/BitNami/wamp/frameworks/codeigniter/conf/httpd-prefix.conf" and save the changes
- Restart Apache in the application manager
Original thread: http://answers.bitnami.com/questions/14148/accessing-codeigniter-in-bitnami-wamp-stack