Urgath1

Hey guys, Got a bad problem with last part of Darkenss Returns quest. Its all about the nocturnal when u actually meet her in Tomb of Twilight, she says her monolog and after she finishes it she goes down and my quest mark does not dissapear, just nothing is happening at all. I heard its a PC/PS3 bug mainly, but i cant find solution to fix it anywhere, any ideas ?