If you're unable to get the "New" button to work in Dashboard, make sure you don't have a "default folder" selected. The default folders appear at the top of your folder structure and include Favorites, My Recent, Recent, Inbox, My Shows, and Trash.
Instead, select an "account folder", which are below the dividing line, and you will be able to access the "New" menu again. Check out this article for more information.
Clicking the "New" Button in an Account folder