First, welcome to Dreamhost. I see this is your first post.
I do not have such a folder in my directory. Maybe it is something new(?). Do you still have it (just empty) or is it “now gone”.
What you should have is: Maildir, logs, a directory for your domain (assuming you signed up for one), and a handful of dot-files (5 IIRC).
My only suggestion is to make a new directory and re-ftp your files.