Is it possible (and I just have the wrong syntax) to do the following:

(defvar base-dir "~/Documents/org/")
(defvar pub-dir "~/Public/notes/")

(setq org-publish-project-alist '(
    ("org"
        :base-directory base-dir
        :base-extension "org"
        :publishing-directory pub-dir
        :recursive t
        :publishing-function org-html-publish-to-html
        :exclude "level-..org"
    )
    ("static"
        :base-directory base-dir
        :base-extension "css\\|js\\|png\\|jpg\\|gif\\|pdf\\|mp3\\|ogg\\|swf"
        :publishing-directory pub-dir
        :recursive t
        :publishing-function org-publish-attachment
    )
("project-root" :components ("org" "static")))
)

When I have the above code and I call (org-publish-project "project-root"),
I get the following error.

Wrong type argument: stringp, base-dir

Thanks.
Tom