Bad value in file-coding-system-alist

["Lennart Borgman (gmail)" <lennart.borgman@gmail.com>]

When trying to customize the variable file-coding-system-alist I get the 
error

   Invalid coding system: po-find-file-coding-system

(Started Emacs with "emacs -Q".)



In GNU Emacs 22.1.50.1 (i386-mingw-nt5.1.2600)
  of 2007-06-17 on LENNART-69DE564
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/g/include'

Important settings:
   value of $LC_ALL: nil
   value of $LC_COLLATE: nil
   value of $LC_CTYPE: nil
   value of $LC_MESSAGES: nil
   value of $LC_MONETARY: nil
   value of $LC_NUMERIC: nil
   value of $LC_TIME: nil
   value of $LANG: ENU
   locale-coding-system: cp1252
   default-enable-multibyte-characters: t

Major mode: Custom

Minor modes in effect:
   encoded-kbd-mode: t
   tooltip-mode: t
   tool-bar-mode: t
   mouse-wheel-mode: t
   menu-bar-mode: t
   file-name-shadow-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
   auto-compression-mode: t
   line-number-mode: t