I have the new version of this add-on, which should be released soon. It will be database-based and completely new algorithms for everything. Older customers will have a chance to upgrade to this version for free by request.
Not sure in what exactly time, but it's almost ready and tested on a very big server. That's why I must say "sorry" for your problem, but the older version of this add-on will be abandoned in the nearest future, and the way it works now, is the latest possible way it works. Even if there's such a bug, I couldn't fix it right now, 'cause I'm working out the new version already.
You could check browser error console first; maybe there is some JS misspelling or CSFR function not included..
Indeed, that's a good advice. May be after upgrading you've missed some template, and this add-on was using CSRF protection, if I remember it correctly.