I have Gwolle guestbook and your add-on installed and both are working fine.
After the recent WP update, I set all my plugins to auto-update.
I noted that the Gwolle add-on cannot be set to auto-update, this is not really a problem. However the counter at the top of the plugin page shows that I have 2 plugins not auto-updating, but in the list only the add-on is not auto-updating, all others are set.
I then noticed that the total number pf plugins (at the top of the page) is one higher than I actually have.
Is the add-on plugin being counted twice?