Hi. The section of the dress that is deforming is assigned to the right hand - but the dress has no bone for the right hand - so poser doesn't know how to assign this to the dress figure.

This would need to be corrected in Daz Studio using the Geometry editor to move the polygons assigned to the rHand to the rForeArm Face Group.

It doesn't take very long to do but you would need to know your way around the Geometry Editor in Daz Studio