I am in Zurich just climbed the stairs in front of the 2 women and i looked at the blue ribbon on the floor and picked it up. the walkthru said to talk to david but cant click on him.
i am using the walkthru by magtro. cant you help please?

It sounds to me like you must have missed a step in the walkthrough that leads up to this, in order to trigger being able to talk to David. What that is, though, I have no way of knowing.

I would look over Chapter 5 of the walkthrough carefully and see what you might have missed.