Same here.

Here's what I did

- installed the becomeroot package (I don't know if that was useful now, but did it anyway, you can try the following steps without becomeroot, it will be less risky)
-In the terminal:
1. cd
2. ls .* (to see the directory)
3. cd .osso_rss_feed_reader
4. rm -r cache

Now it should work.

Since the update, the feedreader has failed to start more than once, I don't know if it has to do with any offending feeds, but I don't think that should happen anyway. I'd start the feed reader from the xterminal, just to see the log in case it fails again, but I don't know how to do it. Went to usr/bin/osso_rss_feed_reader and osso_rss_feed_reader.launch, but that didn't work. I barely defend myself with linux, so I'm out of ideas...