Error in `pre-command-hook`

Hello,

I think it was in an emacs wiki, where I found this nice isearch hook:

(add-hook 'isearch-mode-end-hook '(lambda ()
                                    (when isearch-forward (goto-char=20
isearch-other-end))))

It jumps to the start of the searched part instead of staying at its end=20
which is much nicer for me.

Unfortunately, I get the following error quite often:

(1) (error/warning) Error in `pre-command-hook' (setting hook to nil):=20
(wrong-type-argument integer-or-marker-p nil)

It is reproducible when I press C-s C-home but appears at many other=20
occasions, too.
I turned on "Debug on error" and got this:

Debugger entered--Lisp error: (wrong-type-argument integer-or-marker-p=20
nil)
  goto-char(nil)
  (if isearch-forward (goto-char isearch-other-end))
  (when isearch-forward (goto-char isearch-other-end))
  (lambda nil (when isearch-forward (goto-char isearch-other-end)))()
  run-hooks((lambda nil (when isearch-forward (goto-char=20
isearch-other-end))))
  isearch-done()
  isearch-pre-command-hook()

Unfotrunately, I am not experienced enough to handle this. Could you=20
please help me, as you have done so many times before ?

Many thanks in advance,
Markus Grunwald
Softwareentwicklung

PR=DCFTECHNIK Condition Monitoring GmbH
Oskar-Messter-Stra=DFe 19-21
85737 Ismaning
www.pruftechnik.com
Tel: +49 (0)89 99616177
Fax: +49 (0)89 99616200