At present we are not allowed to create project sharing on dropbox. Project sharing has to be set up on a network system, either in an office, or using a VPN (Virtual Personal Network). Sharing systems like dropbox, box, et cetera use a system that project sharing will not work with at the moment. I have no way of knowing, but I hope this will change in the future.
We are covering Project Sharing in the May archoncad Interactive Workshops, Book Now!