I am in Level 2 of the Vales of Shadows. I have the floor wiped out of enimies, and I know where the switch is!
Why won't the Level 3 door open?

hmm, sounds like a bug. One time, i had trouble with that door. I detected traps in the direction of the door and saw a huge green block around it (detected hidden door). Try detecting the door with a thief or cleric first.

To be honest, that is another problem!
My theif's 3 buttons (Traps, Steal & Stealth) are Blacked out, and have been for some time now.
Will a scroll of "Find Traps" possibly do the trick?

Are you wearing armor? you know your thieving abilities will be nil if you have anything other than leather armor on..

You have to have the wolf talismen if your where I think you are. Its in the room south of the door you cant enter. Then you can pull the lever and go on

Ok, I used a Spell on the door, and then I tried the Trap Finder. Nothing worked.
All it says is ...
"The mechanism that operates this doesn't have a conventional lock, and may be warded against simple spells."

Well, the thing with the Armor solves that Problem, but back to the door, I have Wiped out everyone and checked all the Walls, dead people, etc.

I will try using a Spell Trap to the door, and see what that does!

I believe you need to have all the keys found in the Vale so far in your inventory... 5 or 6 of them, plus the skull badge and the Black Wolf Talisman... give that a shot.

The switch is by the tomb in the centre of the room. Just to the right on the screen, immediately left of one of those pillars. It is just a little dificult to see.

None of the doors with levers can be opened any other way than by a key or activating them with items. you either have missed an item or something..usually these items needed are in the same level you are in to open these mechanicle doors. I believe you need a key for that door as I recall and it should be on that level your in. Best of luck if you still can't figure it out let me know and I'll see if I can locate it for you.