Hello Luca,
It's probably a Memory Limit issue you're having read more about this here:
http://support.wysija.com/knowledgebase/allocated-memory-size-issue/
On a side note: even if we keep an eye on that forum, it's actually difficult for us to follow its activity.
Try as much as you can to write us directly from our contact page which is the direct line to our support team.
Cheers!
Ben
