O Software Center falha na inicialização - tentou o óbvio

Question

O título diz isso.

Se eu correr do Terminal, recebo:

:~$ software-center
2015-02-04 22:12:05,131 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None'
2015-02-04 22:12:05,358 - softwarecenter.region - WARNING - failed to use geoclue: 'org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.Geoclue.Master was not provided by any .service files'
2015-02-04 22:12:05,406 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file
2015-02-04 22:12:05,409 - softwarecenter.plugin - INFO - activating plugin '<module 'webapps_activation' from '/usr/share/software-center/softwarecenter/plugins/webapps_activation.pyc'>'
2015-02-04 22:12:05,514 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open()
2015-02-04 22:12:06,010 - softwarecenter.view.appview - WARNING - ubuntu-almost-fixed-height-mode extension not available
/usr/bin/python: symbol lookup error: /usr/lib/x86_64-linux-gnu/libwebkitgtk-3.0.so.0: undefined symbol: gdk_wayland_display_get_type
administrator@U-8:~$ java version "1.7.0_75"
OpenJDK Runtime Environment (IcedTea 2.5.4) (7u75-2.5.4-1~trusty1)
OpenJDK 64-Bit Server VM (build 24.75-b04, mixed mode)

Eu tenho procurado. Aqui está o que eu tentei:

• Excluindo ~ / .cache / software-center /, muitas vezes, de várias maneiras.
• Limpando e reinstalando o centro de software.
• Removendo PPAs e repositórios de terceiros, Criando uma nova lista de fontes.
• sudo apt-get update & amp; upgrade, muitas vezes!
• sudo rm / var / lib / apt / lists / * -vf sudo apt-get update.

Executando o Xubuntu 14.04

Novas ideias muito apreciadas!