That's not the way you're supposed to go. Vergen is back, do not follow the path where the wooden bust is standing follow the path leading away from the harpies and you'll reach Vergen.
There is an unmarked path in the bushes where there is a small tunnel leading to Vergen. It's opposite the wooden statue... the head of a soldier made of wood. (contrary to the regular soldier's head that's just not made of wood but still is as intelligent )