Comment 3 for bug 785149

I can see previous purchases now, but when I attempt to install one, this happens:

2011-06-01 09:05:43,504 - softwarecenter.backend - INFO - add_repo_add_key_and_install_app() 'private-ppa.launchpad.net/commercial-ppa-uploaders/world-of-goo/ubuntu natty main' '1024R/75254D99' 'World of Goo (already purchased),worldofgoo'
2011-06-01 09:05:43,523 - softwarecenter.backend - ERROR - authenticate_for_purchase failed
Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/backend/aptd.py", line 392, in add_repo_add_key_and_install_app
    yield self.authenticate_for_purchase()
  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 472, in _inline_callbacks
    result = gen.throw(result.type, result.value, result.traceback)
  File "/usr/share/software-center/softwarecenter/backend/aptd.py", line 366, in authenticate_for_purchase
    yield policykit1.check_authorization_by_name(name, action, flags=flags)
AuthorizationFailed: org.freedesktop.PolicyKit.Error.Failed: ('system-bus-name', {'name': ':1.934'}): org.debian.apt.install-purchased-packages

This could perhaps be related to me not using a gnome or unity desktop. I've just got a window manager with no desktop environment.