Restoring Apple Mail Server database

Our mailserver crashed for some reasen a few days ago. Fortunately, we had a backup done by Retrospect and we tried to put the files back to their original location. However, as I launch Mail.app, it retrieves list of messages, but without any headers or content. Any help on this one, I¥m running out of ideas and all our corporate email is stored on the files... Thanks in advance.