+5d6? What? I think maybe you might still be misunderstanding something. When you encounter a haunt, you put it next to your character card. Then roll 1d6 and add 1 (not 1d6) for every haunt currently displayed next to any character card. If the result is 5 or more, you must summon and encounter Iesha.
Yes, I was saying that they were playing it wrong and everytime we encountered a haunt they:
A) automatically added one skill check to the person who encountered the haunt (what you are supposed to do)
B) rolled a 1d6 and added that to EVERYONE'S checks