Форумы / Cotonti / Support / Editors not working on new Siena install

The CKEditor and MarkItUp! are not working on my fresh install of Siena on my localhost.

I've selected CKEditor in the installation process but it's not showing up, instead I have a plain text field.

In the admin panel I noticed that both CKEditor and MarkItUp! were enabled after installing Siena, so I uninstalled MarkItUp! and reinstalled CKEditor but still nothing showed up.

After that I tried it the other way around with MarkItUp! installed and CKEditor uninstalled, but i'm still getting a plain white text field where the editor should be.

http://www.dev-enter.net/files/editor-cotonti.png

Anyone an idea?