Current questions and answers regarding the map editor.

Hey guys, can you help me out? I decided to add an artifact to an existing map, and after saving it in the editor (with the new artifact already added), a bunch of errors appear, and the map breaks, even though it was error-free before (I only added the artifact). How can I prevent these errors from appearing if the map is playable and meets all the requirements (I used to play it, complete it, and everything was fine)? Thanks in advance! ^_^ The map was created and edited in the Heroes of Might and Magic 5 Tribes of the East version 3.0 editor.