Sorry. YES this map was made with WEU. Try opening with that program, thats the only editor I use

As for the 80% ratio, it is 80% for EACH ITEM, not a 80% to fire the spell.
SO, the way it is set up is, it has an 80% to reveal EACH item, so this way, you don't have a 100% chance to reveal ALL items every time.
Sparton, What didn't work. It works fine for me