When I reverted the above change and redumped Emacs, no error was raised.

In GNU Emacs 23.0.60.8 (i686-pc-linux-gnu, GTK+ Version 2.12.9)
 of 2008-10-16 on escher
Windowing system distributor `The X.Org Foundation', version 11.0.10400090
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_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  display-time-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
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<help-echo> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> M-x r e p o r <tab> <return>

Recent messages:
Loading allout...done
Outline mode auto-activation and -layout enabled.
Loading /home/steve/.emacs.d/site-lisp/srb-allout.el (source)...done
Loading /home/steve/.emacs.d/site-lisp/srb-mode-line.el (source)...done
Loading /home/steve/.emacs.d/site-lisp/srb-recentf.el (source)...done
Loading /home/steve/.emacs.d/site-lisp/srb-tabbar.el (source)...done
Loading /home/steve/.emacs.d/site-lisp/tabbar.el (source)...done
Loading /home/steve/.emacs.d/site-lisp/srb-elisp.el (source)...done
Loading `slime': old-style backquotes detected!
Entering debugger...