Topshelf doesn't start

The following bug was reported on Debian's BTS:
http://bugs.debian.org/464734
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Package: topshelf
Version: 0.2.1-1
Severity: serious

Adding topshelf to my gnome panel fails to load the app. It pops up an
error dialog box saying "The panel encountered a problem while loading
"OAFIID:Gnome_Panel_TopShelf"." and allows me to delete it from my
configuration. If I don't delete it, I get this message every time I log in
until I do delete the app.

Here's what it prints to ~/.xsession-errors:
** (gnome-panel:4001): WARNING **: panel-applet-frame.c:1278: failed to
load applet OAFIID:Gnome_Panel_TopShelf:
Failed to resolve, or extend
'!prefs_key=/apps/panel/applets/applet_11/prefs;background=none:;orient=up;size=x-small;locked_down=false

 - David Nusinow

-- System Information:
Debian Release: lenny/sid
 APT prefers unstable
 APT policy: (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.24-1-686 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages topshelf depends on:
ii libgnome2-0 2.20.1.1-1 The GNOME 2 library - runtime file
ii python 2.4.4-6 An interactive high-level object-o
ii python-gtk2 2.12.1-1 Python bindings for the GTK+ widge

Versions of packages topshelf recommends:
ii yelp 2.20.0-1 Help browser for GNOME 2

-- no debconf information