When you Save and exit to Middle Earth Each time make sure that when the Treasure Item box comes up that you see the item being counted into the box items, DO NOT SKIP. I have had this problem with the Weathertop level, but I have also beenm reading that people havce had this problem on other levels as well, so for safty sake, do this process for the Treasure Items for all levels and I believe you will finish the game. But there is a catch, you have to start a whole different Save for this to work. What you do is start freeplay and collect one of the items and then save the game and exit to Middle Earth, do this three times without getting anything else on that level and you will get your mithril block.
I have the same problem you people are having, where you complete freeplay and the Treasure Items do not register.
