after installing webcamstudio, cheese won't start

[Manuel Valentin]

After I have installed webcamstudio, cheese isn't able to start without having webcamstudio opened.

if I execute cheese in terminal, it shows the following error:
** (cheese:5246): CRITICAL **: cheese_camera_device_get_uuid: assertion `CHEESE_IS_CAMERA_DEVICE (device)' failed
Segmentation fault (core dumped)

Opening cheese with webcamstudio opened occurs without problems.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: cheese 3.4.1-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
Uname: Linux 3.2.0-29-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu12
Architecture: amd64
Date: Mon Aug 13 17:20:57 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MachineType: Dell Inc. XPS 8300
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RelatedPackageVersions:
 cheese 3.4.1-0ubuntu2
 cheese-common 3.4.1-0ubuntu2
SourcePackage: cheese
UpgradeStatus: Upgraded to precise on 2012-04-28 (107 days ago)
dmi.bios.date: 10/17/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A06
dmi.board.name: 0Y2MRG
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA06:bd10/17/2011:svnDellInc.:pnXPS8300:pvr:rvnDellInc.:rn0Y2MRG:rvrA01:cvnDellInc.:ct3:cvr:
dmi.product.name: XPS 8300
dmi.sys.vendor: Dell Inc.