You need to have Microsoft Project Professional 2013 installed and configured to connect to a profile for this Project Web ...

You need to have Microsoft Project Professional 2013  installed and configured to connect to a profile for this Project Web App site. You can do so by opening Project Professional, and adding the URL of a site in your PWA site collection to the Manage Accounts dialog in the Info tab of the File menu. Then, close Project Professional, and open it connected to this profile before trying this operation again. If Project Professional is already loaded, ensure that it is connected to the profile for this Project Web App site and that there are no dialog boxes open.