I think you should check that the user running HW has permission to write a file in the folder into which your SaveAs request is trying to write. How to do this depends on the OS you are running.
Have you tried Save and let HW choose the name? Does this fail in the same way? If this works try your SaveAs using the same folder HW used.
Diagnostic reports are normally sent from
https://www.hauptwerk.com/forms/support/ which you reach forms Support on the main menu bar of the website and then select Support Ticket.
Iain