Thanks Jerakeen,
Yes I still get the "icy presence grows stronger" message but nothing happens.
You are right I must have fled, leaving the ghost in the circle.
I tried the console line and when I went there I had a message box as if it was the first time I came here, but then nothing.
I spend some time in the circle, used combat mode to make things faster, still nothing.
I justed started a new game in Torment, this time she won't stand a chance