Make sure that when you attempt to place a home that you look all over the plot for items that might block placement. I almost gave up on placement but instead took a char to Fel to see if the house was placed in the same spot there. I found a keep placed in the same spot and I went over the plot section by section with a small 7 x 7 home to see what area was blocked. I found an old pot of stew that looked like a round mushroom on the ground and the stew was blocking placement. I was lucky and got a GM who was nice enough to move the stew and the keep immediately placed. So make sure you use control shift and check each small section of the plot to find the blocking items.