Software Center and Update Manager will not start after downloading Full Circle Magazine

After a routine software update via the update manager and after downloading Full Circle Magazine, I found that neither the software center nor the update manager would start when clicked on the launcher. The software center seemed to have hung during the Full Circle Magazine install, and I killed it after about 15 min. Afterwards, Full Circle Magazine opened OK and seemed to readable.

The update manager does report the following error message:

"Could not initialize the package information
An unresolvable problem occurred while initializing the package information.
Please report this bug against the 'update-manager' package and include the following error message:

'E:Opening /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_fullcircle-issue-56_ubuntu.list - ifstream::ifstream (13: Permission denied)'"

I tried both warm and cold reboots.

I tried running 'ubuntu-bug update-manager' in terminal, but only received the following message:

"Could not determine the package or source package name."

I also tried running ubuntu-bug with the process ID for the update manager from the system monitor, but just received the following message.

"The specified process ID does not belong to a program."

All of the above error conditions are repeatable.

I am reporting this as bug per instructions from the above error messages.

Thank you.