Synaptic Package Manager goes into infinite loop

After a fresh reboot and starting no other processes, I started the Synaptic Package Manager, selected Settings -> Preferences, and changed the setting for General->System Upgrade from "Smart Upgrade" to "always ask." The system monitor then showed 100% CPU usage, but when I look at the processes in System Monitor, I don't see more than about 25% CPU usage total from the processes displayed. When I use "top" instead, I see all the CPU time, with process "synaptic" taking between 50% and 66% of the CPu time. In the System Monitor, process "at-spi-registryd" takes between 3% and 20% of CPU time. System Monitor says that at-spi-registryd process is "waiting channel" as "poll_schedule_timeout." I guess top doesn't show the state of the synaptic process.

In any case, CPU time stays at 100% usage for at least half an hour, and the synaptic package manager never returns to a usable state. I have to terminate the process.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: at-spi 1.31.91-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.35-28.50-generic 2.6.35.11
Uname: Linux 2.6.35-28-generic i686
Architecture: i386
Date: Fri Jun 24 13:19:43 2011
ExecutablePath: /usr/lib/at-spi/at-spi-registryd
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: at-spi
XsessionErrors:
 (gnome-power-manager:1808): Gtk-WARNING **: A floating object was finalized. This means that someone
 (polkit-gnome-authentication-agent-1:1844): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
 (synaptic:2005): Gtk-WARNING **: GtkSpinButton: setting an adjustment with non-zero page size is deprecated
 (synaptic:2005): Gtk-WARNING **: GtkSpinButton: setting an adjustment with non-zero page size is deprecated
 (synaptic:2005): Gtk-WARNING **: GtkSpinButton: setting an adjustment with non-zero page size is deprecated