I have a similar problem:
My vBGallery tables all have the prefix "adv_gallery_", but a simple renaming won't help since there is no table named "adv_gallery_settinggroup".... I guess I would need a lower version than 2.3 as an upgrade step, but I can only download 2.3.
Can someone help me, please?
By the way, my gallery currently consists of 9,765 pictures using 1.50 GB harddisc space. I really would like to keep all data.