bug#1585: 23.0.60; vc-dir-toggle-mark error

[robert]

There's a button for vc-dir-toggle-mark (in a *vc-dir buffer)
in the toolbar but when I try to use it, I get the error:

Wrong type argument: integer-or-marker-p, nil

with the traceback 

  vc-dir-toggle-mark((tool-bar))
  call-interactively(vc-dir-toggle-mark nil nil)



In GNU Emacs 23.0.60.5 (i686-pc-linux-gnu, GTK+ Version 2.14.4)
 of 2008-12-15 on robert-laptop
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
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: en_GB.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t