Create a new project from the beginning, first thing firsts. Go to Map, Map Properties and make sure it is creating external files for house and spawn. Also, its dimensions and map/client version are correct. Try saving it as a new project, if it creates any blank file named project-spawn.xml, project-house.xml then you're ready to go. Open your project again, go to File, Import Monster and NPCs, once these are imported it should work properly.