Impossible to enable Desktop Effects

[Elephantman]

Binary package hint: xorg

Using Kubuntu 11.04 beta2.
In systemsettings, I go in "Desktop effects", check the "Enable destop effects" option and Apply.
That produces an error message that says it's not possible to enable Desktop effects, and that I should check my xorg config.

The desktop effects worked fine with kubuntu 10.10 and kde 4.6.2, so it seems to be a regression in Natty.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: xorg 1:7.6+4ubuntu3
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: kwin
DRM.card0.DP.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.DP.2:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.DP.3:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.HDMI.A.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.HDMI.A.2:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.HDMI.A.3:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.VGA.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.eDP.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1600x900 1600x900
 edid-base64: AP///////wAw5J4CAAAAAAATAQSVIhN4AhvlnllQmCYOUFQAAAABAQEBAQEBAQEBAQEBAQEBgCVAgGCEGjAwIDUAWMIQAAAYFBlAjGCEFjAwIDUAWMIQAAAYAAAA/gBQNzI3UoAxNTZXRDEKAAAAAAAAQTEZAAAAAAkBCiAgANo=
Date: Sat Apr 16 19:14:05 2011
DistUpgraded: Log time: 2011-03-30 14:37:53.231444
DistroCodename: natty
DistroVariant: kubuntu
DkmsStatus:
 vboxhost, 4.0.4, 2.6.38-7-generic, x86_64: installed
 vboxhost, 4.0.4, 2.6.38-8-generic, x86_64: installed
 nvidia-current, 270.41.03, 2.6.38-8-generic, x86_64: installed
GraphicsCard:
 Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:040b]
InstallationMedia: Kubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
MachineType: Dell Inc. Latitude E6510
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcEnviron:
 LANGUAGE=
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=f61c55e3-c2b0-4549-a5c8-b9de8675374d ro quiet splash vt.handoff=7
Renderer: Unknown
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to natty on 2011-03-30 (17 days ago)
dmi.bios.date: 11/20/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A06
dmi.board.name: 02K3Y4
dmi.board.vendor: Dell Inc.
dmi.board.version: A02
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA06:bd11/20/2010:svnDellInc.:pnLatitudeE6510:pvr0001:rvnDellInc.:rn02K3Y4:rvrA02:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6510
dmi.product.version: 0001
dmi.sys.vendor: Dell Inc.
version.compiz: compiz N/A
version.ia32-libs: ia32-libs 20090808ubuntu12
version.libdrm2: libdrm2 2.4.24~glasen~maverick~ppa2
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu1
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu3
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu7
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7