The most common problem people have with this puzzle is that the torch goes out and you can't see the doors. Is this what's happening to you?
If you lit the torch and it went out, you'll have to go back to a previous save when it wasn't lit yet. When you walk in that room, stay close to the wall and I think it's 2 or 3 clicks to the right, look all the way up on the wall and you'll see where the torch goes and has to be lit. Save your game before lighting it because you have to move very quickly across the room to the altar and back again before it goes out again.
I hope that helps.