Un plug-in manque dans votre installation GStreamer

J'ai ce problème avec mon lecteur de musique (Rhythmbox Music Player) sous Linux (SL)

ça dit:

Couldn't start playback
Your GStreamer installation is missing a plug-in

J'ai tous les plug-ins installés sur mon système

[alexus@wcmisdlin02 ~]$ yum list gstreamer-plugins-*
Loaded plugins: refresh-packagekit
http://10.52.208.221/yum/extras/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
Installed Packages
gstreamer-plugins-bad-free.i686                                                                                0.10.19-2.el6                                                                   @sl                                          
gstreamer-plugins-bad-free.x86_64                                                                              0.10.19-2.el6                                                                   @anaconda-ScientificLinux-201107271550.x86_64
gstreamer-plugins-bad-free-extras.i686                                                                         0.10.19-2.el6                                                                   @sl                                          
gstreamer-plugins-bad-free-extras.x86_64                                                                       0.10.19-2.el6                                                                   @sl                                          
gstreamer-plugins-base.i686                                                                                    0.10.29-1.el6                                                                   @sl                                          
gstreamer-plugins-base.x86_64                                                                                  0.10.29-1.el6                                                                   @anaconda-ScientificLinux-201107271550.x86_64
gstreamer-plugins-good.i686                                                                                    0.10.23-1.el6                                                                   @sl                                          
gstreamer-plugins-good.x86_64                                                                                  0.10.23-1.el6                                                                   @anaconda-ScientificLinux-201107271550.x86_64
Available Packages
gstreamer-plugins-bad-free-devel.i686                                                                          0.10.19-2.el6                                                                   sl                                           
gstreamer-plugins-bad-free-devel.x86_64                                                                        0.10.19-2.el6                                                                   sl                                           
gstreamer-plugins-bad-free-devel-docs.x86_64                                                                   0.10.19-2.el6                                                                   sl                                           
gstreamer-plugins-base-devel.i686                                                                              0.10.29-1.el6                                                                   sl                                           
gstreamer-plugins-base-devel.x86_64                                                                            0.10.29-1.el6                                                                   sl                                           
gstreamer-plugins-base-devel-docs.noarch                                                                       0.10.29-1.el6                                                                   sl                                           
gstreamer-plugins-good-devel.i686                                                                              0.10.23-1.el6                                                                   sl                                           
gstreamer-plugins-good-devel.x86_64                                                                            0.10.23-1.el6                                                                   sl                                           
[alexus@wcmisdlin02 ~]$ 

les seuls paquets qui manquent sont les paquets devel ... des idées?

c'est ce qui manquait ...

[alexus@wcmisdlin02 ~]$ sudo tail -1 /var/log/yum.log 
Nov 15 12:43:38 Installed: gstreamer-ffmpeg-0.10.11-1.el6.rf.x86_64
[alexus@wcmisdlin02 ~]$