gnome-control-center crashes when trying to add a wallpaper from a file

I opened System Settings, selected Appearance, changed the Wallpaper dropdown to Pictures folder, clicked the + to select a file (since my wallpapers are in a subfolder of Pictures), and double-clicked my wallpapers folder. gnome-control-center appeared to hang for a couple of seconds and then crashed. Reproduced several times. I just installed precise this morning so I don't know whether this ever worked.

If I place backgrounds in the Pictures folder itself (not a subfolder) they show up automatically and can be selected. However, clicking the + and double-clicking an image file also causes a crash.

I assume I'll need to install some debug symbols for the stack trace to be useful; can you tell me which packages I should install them for? Thanks.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: gnome-control-center 1:3.2.2-2ubuntu10
ProcVersionSignature: Ubuntu 3.2.0-16.25-generic 3.2.6
Uname: Linux 3.2.0-16-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
Date: Wed Feb 15 12:43:49 2012
ExecutablePath: /usr/bin/gnome-control-center
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120215.1)
ProcCmdline: gnome-control-center
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANGUAGE=en_CA:en
 LANG=en_CA.UTF-8
SegvAnalysis:
 Segfault happened at: 0x7fdec14add80 <g_type_check_instance_cast+16>: mov (%rdi),%rax
 PC (0x7fdec14add80) ok
 source "(%rdi)" (0xffffffffc405e870) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: gnome-control-center
StacktraceTop:
 g_type_check_instance_cast () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
Title: gnome-control-center crashed with SIGSEGV in g_type_check_instance_cast()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip libvirtd lpadmin plugdev sambashare sudo wireshark
usr_lib_gnome-control-center:
 activity-log-manager-control-center 0.9.1-0ubuntu2
 deja-dup 21.2-0ubuntu4
 gnome-bluetooth 3.2.2-0ubuntu1
 indicator-datetime 0.3.1-0ubuntu5