nonexistent manpage gives incorrect error message

[robert]

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

emacs -Q (from cvs updated this morning)
M-x man
xxx
gives the error Man-goto-page: Can't find the nil manpage


If emacs crashed, and you have the emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
/develop/emacs/etc/DEBUG for instructions.


In GNU Emacs 22.0.50.14 (i686-pc-linux-gnu, GTK+ Version 2.6.4)
 of 2005-07-21 on faure.chezmarshall.freeserve.co.uk
X server distributor `Mandrakelinux (X.Org X11 6.8.2, patch level 7.1.102mdk)', 
version 11.0.60802000
configured using `configure '--with-x-toolkit=gtk''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: en_GB
  value of $LC_CTYPE: en_GB
  value of $LC_MESSAGES: en_GB
  value of $LC_MONETARY: en_GB
  value of $LC_NUMERIC: en_GB
  value of $LC_TIME: en_GB
  value of $LANG: en_GB
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  show-paren-mode: t
  recentf-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  auto-compression-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t
  next-error-follow-minor-mode:  Fol

Recent input:
- e r r <tab> <return> n i <backspace> <backspace> 
t <return> <escape> x m a n <return> x x x <return> 
<up> <down> <down> <down> <down> <down> C-x C-b C-x 
o <down> f C-a <up> <up> <up> <up> <up> <up> <up> <up> 
<escape> C-g <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <menu-bar> <help-menu> 
<report-emacs-bug>

Recent messages:
Invoking man xxx in the background
Please wait: formatting the xxx man page...
xxx man page formatted
error in process sentinel: Man-goto-page: Can't find the nil manpage
error in process sentinel: Can't find the nil manpage
Invoking man xxx in the background
Please wait: formatting the xxx man page...
xxx man page formatted
Man-goto-page: Can't find the nil manpage
Loading emacsbug...done