[Orgmode] Export to iCal raises (error "Selecting deleted buffer")

[Paul R]

iCal export crashes when :
 - from dirary, C-x C-w file.ics
 - from org buffer C-c C-e I or C-c C-e c

It works when exporting with C-c C-e i.

Emacs 22.1, org version 6.02 on Ubuntu.

When crashing, the stack trace is :

Debugger entered--Lisp error: (error "Selecting deleted buffer")
  byte-code("(...)" [b sexp sexp-buffer org-agenda-skip 0 forward-sexp 1 "\n" 
princ org-diary-to-ical-string] 3)
  org-print-icalendar-entries(combine)
  byte-code("(...)" [file combine dir buffer-file-name ical-file ical-buffer 
org-check-agenda-file org-get-agenda-file-buffer file-name-as-directory 
file-name-sans-extension file-name-nondirectory ".ics" erase-buffer symbol-name 
t org-start-icalendar-file org-print-icalendar-entries 
org-finish-icalendar-file save-buffer run-hooks 
org-after-save-iCalendar-file-hook boundp org-wait sit-for org-category 
category standard-output started org-icalendar-combined-name files] 5)
  org-export-icalendar(combine "~/emacs/data/org/perso.org" 
"~/emacs/data/org/boulot.org")
  apply(org-export-icalendar combine ("~/emacs/data/org/perso.org" 
"~/emacs/data/org/boulot.org"))
  (let ((org-agenda-marker-table ...) (org-icalendar-verify-function ...) 
(org-combined-agenda-icalendar-file file)) (apply (quote org-export-icalendar) 
(quote combine) (org-agenda-files)))
  (cond ((string-match "\\.html?\\'" file) (set-buffer ...) (when ... ... ... 
...) (write-file file) (kill-buffer ...) (message "HTML written to %s" file)) 
((string-match "\\.ps\\'" file) (ps-print-buffer-with-faces file) (message 
"Postscript written to %s" file)) ((string-match "\\.ics\\'" file) (let ... 
...)) (t (let ... ... ... ... ... ...)))
  (save-window-excursion (cond (... ... ... ... ... ...) (... ... ...) (... 
...) (t ...)))
  (save-excursion (save-window-excursion (cond ... ... ... ...)))
  (let nil (save-excursion (save-window-excursion ...)) #<buffer *Org Agenda*>)
  eval((let nil (save-excursion (save-window-excursion ...)) #<buffer *Org 
Agenda*>))
  org-let(nil (save-excursion (save-window-excursion (cond ... ... ... ...))) 
#<buffer *Org Agenda*>)
  org-write-agenda("~/cleanMe/lalilo.ics")
-- 
      Paul