Stuck in Chapter 5 (spoilers)

I'm stuck on The Final Element phase of the Armor quest. I've got all the other bits, and Kalkstein tells me I need to go to the Old Mine and cast a combination of Signs on the rock in there. He says Aard, Igni, then Aard again. Every time I do that combination of signs on the Wayfarer's Stone in the Mine it says "That's not working. I should try a different combination." I've tried that combination, and many others, all with the same (or no) result.

Either I've hit a bug and won't be able to get the armor, or I'm doing something wrong.

Edit: As usual, 2 minutes after asking for help I find it myself. I was in the wrong cave.

If I remember right you have to reverse them when you try to leave.

Btw speaing of kalkstein… Is he a gnome? Atleast geralt says at some point that kalkstein had gnomish orgins/blood or something?

Kalkstein doesn't appear in any of the books so all the background info comes from the game alone but he doesn't have gnomic features as described by Sapkowski. So your guess is as good as mine….. Halfcast possibly?

I know the references you speak of Dez. I guess it's subjective but I was of the impression that the references Geralt made were simply sarcastic humor based on the scheming and behavior of Kalkstein, and not to be taken literally.