I am attempting to complete the penultimate quest for the Dragoon warrior class "Fatal Seduction" and when I want to go to the red circle where the quest is supposed to occur there is no icon of any kind within the red circle to indicate where I am supposed to utilize the flute to commence the required battle. I had been searching for over an hour and have only seen text to indicate where smaller monsters are.

How can this be dealt with so that I can complete the required task?