@omironia: sorry about that, it's somewhat of a know issue that can happen when a feed is deleted. Next version (unavailable yet) handles it much better.
Quick fix is to open X-terminal and run:
mv /home/user/.feeding/feeds.pickle /home/user
That will reset your list of feeds though . If you have a long list of feeds you'd rather not have to re-import, I can probably fix it manually if you send me the feeds.pickle file.