Hi Philippe,
I had the same problem. Restoring database "solved" the problem, but if you go to configuration->product update it shows another error (something like: "You currently using Revive Adserver 3.0.2 - database is stemped as 2.8.11" and "unable to look for updates"). How did you solve THIS problem?
Hope to hear from you soon (this post is the only one I found on the www which go into my problem)
Best regards
Lisa