The last available database backup is dated 2-Sept so all the posts and topics posted after that date were completely lost.
Sorry for the inconvenience caused by this problem, but I did the most I can do to save as much data as possible, sorry guys
P.S. : While trying to fix the error I upgraded to the Invision Power Board v1.2 software to see if it would help in our situation.
Well, it didn't; but we are now enjoying the new features of the IPB 1.2.
Best regards,