Let me start with an explanation of the situation. I started a wordpress-hosted blog. After realising the limiations, I created a self-hosted blog using the open-source WordPress distribution (WordPress.org). After changing my mind and wanting to use the wordpress-hosted blog, I decided to uninstall my self-hosted blog from my host.
At some point during the configuration of my self-hosted blog, I have managed to “link” my WordPress account to the self-hosted domain. The problem now is, that domain is still showing under my list of blogs on wordpress.com, but it no longer exists.