I just noticed the Red outline in the first picture. I take it that is some type of prop to keep the skirt from falling too close to the figure.  If so that has a distance offset and the skirt has a distance offset and finally the dress has a distance offset.  When you add all of them up that can cause the cloth to not drop as it is approaching the area where it is supposed to stay away from.  Once you have the Skirt draped turn it into a choreographed part and it will follow the body around as the simulation form that part has been done.  And under properties for the skirt turn the soft cloth distance down to a very low number and then run the Dress Simulation.  You may have to also turn down the distance on the Red Outlined objects properties.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13, 14