Did you just get the error:
"An unrecoverable problem occurred while opening the file! See Console log for more information."
This is very rare, and due to the Templates folder not being installed correctly. If the Screenwriter 6.5 templates don't get installed in the correct location, then the Default FD templates used for Final Draft importing aren't available, so Final Draft imports always fail.
The solution is to re-install Screenwriter 6.5. Make sure you are logged in to a user that is an administrator.