Strange "non-existent agenda file" message

[pinard@iro.umontreal.ca (François Pinard)]

Hi, Org people.

I have a few notes about Org mode which I intend to present to my
coworkers at our next meeting, if time permits.  This evening, I just
pushed them together (the notes, not the coworkers!) in a file with the
idea of creating a few beamer slides.  And doing so, experimenting a bit
with the feature :-).

Command "C-c C-e d" yields this strange message:

  non-existent agenda file
  ~/fp/notes/Bureautique/Org_mode_Présentation.org.
  [R]emove from list or [A]bort?

This is not an agenda file, and I've no reason to turn it into an agenda
file either.  Is there a relation between a beamer presentation and the
agenda?  Why the question?  What is the meaning of the message?

If I add a (debug) call at beginning `org-check-agenda-file' in org.el,
I see:


Debugger entered: nil
  org-check-agenda-file("/home/pinard/fp/notes/Bureautique/Org_mode_Présentation.org")
  byte-code("\306\b!\203\f.\bq\210\202.\0\307\b!\210\310\b!q\210~\210\311 .\312 \210\313\n\v\".\313\f.\".\313.\x17.\x18\".\x17\313.\x19.\x1a\".\x19\313.^[.\x1c\".^[\212\314ed.\x1d#\210.\x1e\203k.eb\210\315.\x1f\316\317#\203k.\320\317!\203O.\321\322 \323\317!. #\210\202O.eb\210\324.!.\"\".#\315.#\316\317#\203\214.\321\325\224\323\317!.$#\210\202v.)\326	!\207" [file bmp org-todo-keywords-for-agenda org-todo-keywords-1 org-done-keywords-for-agenda org-done-keywords bufferp org-check-agenda-file org-get-agenda-file-buffer buffer-modified-p org-refresh-category-properties append remove-text-properties re-search-forward nil t org-at-heading-p add-text-properties point-at-bol org-end-of-subtree format 0 set-buffer-modified-p org-todo-keyword-alist-for-agenda org-todo-key-alist org-drawers-for-agenda org-drawers org-tag-alist-for-agenda org-tag-alist pall org-agenda-skip-archived-trees rea pa org-heading-keyword-regexp-format org-comment-string re pc] 4)
  org-prepare-agenda-buffers(("/home/pinard/fp/notes/Bureautique/Org_mode_Présentation.org"))
  org-map-entries((progn (setq props (org-entry-properties nil ...)) (if (and ... ...) (push ... props)) (put-text-property (point-at-bol) (point-at-eol) (quote org-props) props)))
  org-beamer-after-initial-vars()
  run-hooks(org-export-latex-after-initial-vars-hook)
  org-export-as-latex(nil nil nil nil nil nil)
  org-export-as-pdf(nil)
  org-export-as-pdf-and-open(nil)
  call-interactively(org-export-as-pdf-and-open)
  org-export(nil)
  call-interactively(org-export nil nil)


I do not understand why nor how org-map-entries (likely line 478 in
org-beamer.el) ends up in calling org-prepare-agenda-buffers.  The SCOPE
argument or org-map-entries is implied to nil, isn't it?


François