Traceback (most recent call last): File "/usr/share/software-center/softwarecenter/models/appstore.py", line 508, in on_get_value icon_file_name) File "/usr/share/software-center/softwarecenter/models/appstore.py", line 387, in _download_icon_and_show_when_ready url = get_distro().get_downloadable_icon_url(cache, pkgname, icon_file_name) File "/usr/share/software-center/softwarecenter/distro/Ubuntu.py", line 219, in get_downloadable_icon_url full_archive_url = cache[pkgname].candidate.uri File "/usr/share/software-center/softwarecenter/apt/aptcache.py", line 115, in __getitem__ return self._cache[key] TypeError: 'NoneType' object is not subscriptable