Comment 1 for bug 929910

I found that the file

 /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_fullcircle-issue-56_ubuntu.list

only had root read permission, unlike the rest of the files in that directory. When I added universal read permission, the software center and the update manager started running again. This solved my problem.

My original bug report is probably inappropriate, but perhaps the default permissions for the above file need to include universal read permission.

Sorry for any inconvenience here.

My problem is solved.