Ok I found the door in the big crypt that you were talking about. Can't believe I overlooked it. Now my problem is the room after the big door when I pull the switch on the pillar. All the undead just cream my party. They don't stand a chance. There seemed to be about 30-40 creatures in the room. Any tips on how to get through them.

Have your cleric turn undead, that gets the little skeletons to run away for a bit so you can concentrate on the big ones. And do the room in sections, don't go storming into the middle of it. I went around the sides and was able to take the undead on in small groups. And try not pulling the switch until after you take out the ones in the room, that's what I did and I didn't have much of a problem with this room.