Impossible de lancer la logithèque Ubuntu

Bonjour,
Je viens d'installer Ubuntu 14.10 sur mon pc et je ne parviens plus à accéder à la logithèque et c'est un peu handicapant... Je débute avec Ubuntu et je ne sais pas quoi faire :(
en tapant software-center dans la commande, j'obtiens ceci:

(software-center:3260): Gtk-WARNING **: Theme parsing error: gtk.css:50:39: Failed to import: Erreur à l'ouverture du fichier : Aucun fichier ou dossier de ce type
2015-02-22 18:07:11,115 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None'
2015-02-22 18:07:11,654 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file
2015-02-22 18:07:11,657 - softwarecenter.plugin - INFO - activating plugin '<module 'webapps_activation' from '/usr/share/software-center/softwarecenter/plugins/webapps_activation.pyc'>'
2015-02-22 18:07:11,726 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open()
2015-02-22 18:07:12,248 - softwarecenter.backend.reviews - WARNING - error creating bsddb: '(22, 'Argument invalide -- BDB0054 illegal flag combination specified to DB_ENV->open')' (corrupted?)
2015-02-22 18:07:12,249 - softwarecenter.backend.reviews - ERROR - trying to repair DB failed
Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/backend/reviews/__init__.py", line 358, in _save_review_stats_cache_blocking
    self._dump_bsddbm_for_unity(outfile, outdir)
  File "/usr/share/software-center/softwarecenter/backend/reviews/__init__.py", line 377, in _dump_bsddbm_for_unity
    0600)
DBInvalidArgError: (22, 'Argument invalide -- BDB0054 illegal flag combination specified to DB_ENV->open')
/usr/lib/python2.7/dist-packages/gi/overrides/GLib.py:535: Warning: Source ID 68 was not found when attempting to remove it
  return super(MainContext, self).iteration(may_block)
Traceback (most recent call last):
  File "/usr/bin/software-center", line 183, in <module>
    app.run(args)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1378, in run
    self.show_available_packages(args)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1316, in show_available_packages
    self.view_manager.set_active_view(ViewPages.AVAILABLE)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/session/viewmanager.py", line 150, in set_active_view
    view_widget.init_view()
  File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/availablepane.py", line 227, in init_view
    self.cache, self.db, self.icons, self.apps_filter)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/lobbyview.py", line 67, in __init__
    apps_limit=0)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview.py", line 130, in __init__
    self._cache_art_assets()
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview.py", line 151, in _cache_art_assets
    surf = cairo.ImageSurface.create_from_png(self.STIPPLE)
cairo.Error: file not found

Que faire? :(
Merci de pouvoir me répondre