Switching to a new node in org mode

Question

These are the settings in my .emacs for updating in org mode:

(setq org-refile-targets (quote ((nil :maxlevel . 10)
                             (org-agenda-files :maxlevel . 10))))

(setq org-refile-use-outline-path t)
(setq org-outline-path-complete-in-steps nil)
(setq org-refile-allow-creating-parent-nodes (quote confirm))

Correcting the existing path works as it should, but I cannot create a new node and refile for it, since the last line should allow me to do this. When I redo the path, for example:

Existing node"/New node"

I get an error message:

Please save the buffer to a file before refiling

Presumably this means emacs can identify the target file, but the target is set using a string org-refile-targets, so what's wrong?