compiz crashed with SIGSEGV in sigc::signal_base::impl()

[Lorem Daijoh]

Binary package hint: unity

Compiz (or Unity, I'm not sure) crashes every time any of the Compiz plugins is disabled or enabled with CCSM. It manages to restart itself though.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: unity 3.8.4-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: wl
Architecture: i386
CrashCounter: 1
Date: Mon Apr 11 02:23:13 2011
ExecutablePath: /usr/bin/compiz
LiveMediaBuild: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
ProcCmdline: compiz
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_IE.UTF-8
 LC_MESSAGES=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x61fe3d <_ZNK4sigc11signal_base4implEv+29>: mov 0x4(%edi),%esi
 PC (0x0061fe3d) ok
 source "0x4(%edi)" (0x0000007c) not located in a known VMA region (needed readable region)!
 destination "%esi" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 sigc::signal_base::impl() const () from /usr/lib/libsigc-2.0.so.0
 sigc::signal_base::connect(sigc::slot_base const&) () from /usr/lib/libsigc-2.0.so.0
 UnityScreen::UnityScreen(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 CompPlugin::VTableForScreenAndWindow<UnityScreen, UnityWindow>::initScreen(CompScreen*) () from /usr/lib/compiz/libunityshell.so
 CompManager::initPlugin(CompPlugin*) ()
Title: compiz crashed with SIGSEGV in sigc::signal_base::impl()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare