ddeclient very slow in emacs 22.1

[Tom]

I work a lot with LaTeX and i use emacs for editing my code ...
I try this function :

(global-set-key [f1] 'maFonction)
(defun maFonction() (interactive)
    (save-excursion
    (set-buffer (get-buffer-create " *ddeclient*"))
    (erase-buffer)
    (insert (concat "[DocClose(\"rr.pdf\")]" ))
    (call-process-region (point-min) (point-max)
                         "ddeclient" t t nil "acroview" "control")
    (if (= 0 (string-to-int (buffer-string))) t nil)))

that run very slowly with emacs 22.1.1 (i386-mingw-nt5.1.2600)
and run fast with version 21.3

It's a bug or i have something to do especial