The horseshoes are spawned when your party first enters a map. They are dropped from the sky, hit the terrain, and slide downhill. They can -- and do in those regions -- often end up inside a building that you can't access. You can look inside those buildings by positioning your viewpoint at the corners of the buildings where two brushes (flat polygons) come together. When you see your horseshoe, use Telekinesis to fetch it....Or restart the map from a previous savegame and hope for better luck with the sliding horseshoes.
Pertaining to your original question, I can't give you any more help than what Peter2 had to offer. Heck, I couldn't have given you *that* much!
