ok, that is now a little bit confusing for me... i used the backup/restore utlity from within zenphoto... i think it has something to do with updating to a nightly and downgrading back again (there were some database structure changes) - well, long story short, i restored quite an old backup, got my pages back, restored a newer one and got my album changes back - so i'm happy, even if i don't really understand why it worked this way