(setq result 255))))
                  (let ((default-directory "/")
                        (inbox-info (nnmail-parse-spool-file-name inbox)))
-                   (setenv (nnmail-spool-mailhost inbox-info))
+                   (setenv "MAILHOST" (nnmail-spool-mailhost inbox-info))
                    (setq result
                          (apply
                           'call-process
                             (expand-file-name
                              nnmail-movemail-program exec-directory)
                             nil errors nil 
-                            (nnmail-spool-maildrop inbox-info) tofile)
+                            (concat "po:" (nnmail-spool-maildrop inbox-info))
+                            tofile)
                            (when nnmail-internal-password
                              (list nnmail-internal-password)))))))
                (push inbox nnmail-moved-inboxes)