I have the same thing for certain shows - for instance, NCIS
S11E15 and 16 won't download with that error, even when clicking on
them directly. Castle had a similar problem with a previous episode
- S06E16, and then the next episode is working again. but S06E16 is
still bad. Besides the obvious problem of shows being skipped and
no way to tell without looking at the log, TVShows never moves on
from the unsuccesful download to try the latest one, I had to
delete the feeds, shut the program down, and recreate them to get
it to move on.
The magnet links option works for me as well - weirdly, since
most of the torrents worked anyway. But it fixes the couple that
were broken. Since my torrent client runs on a remote server and is
managed via its web interface, had to install
transmission-remote-gui to use as the local default application to
handle magnet links.