Comment 1 for bug 852003

I also had this issue, inside the non-admin user. If can be useful, this is my trace:

ubuntuone-control-panel-gtk
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/gui/gtk/gui.py", line 1573, in on_show_management_panel
    self.management.load()
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/gui/gtk/gui.py", line 1502, in load
    self.services.load()
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/logger.py", line 82, in inner
    res = f(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/gui/gtk/gui.py", line 1173, in load
    logger.info('load: has_desktopcouch? %r', self.has_desktopcouch)
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/gui/gtk/gui.py", line 1145, in has_desktopcouch
    return self.package_manager.is_installed(DESKTOPCOUCH_PKG)
  File "/usr/lib/python2.7/dist-packages/ubuntuone-control-panel/ubuntuone/controlpanel/gui/gtk/package_manager.py", line 49, in is_installed
    cache = apt.Cache()
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 93, in __init__
    self.open(progress)
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 140, in open
    self._list.read_main_list()
SystemError: E:Apertura di /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_fullcircle-issue-50_ubuntu.list - ifstream::ifstream (13: Permesso negato)