"Install additional software " button doesn't find required plugin when behind proxy

[Joshua Lock]

Ubuntu version information:
Description: Ubuntu 12.10
Release: 12.10

Rhythmbox version information:
  Installed: 2.97-1ubuntu5
  Candidate: 2.97-1ubuntu5
  Version table:
 *** 2.97-1ubuntu5 0
        500 http://us.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages
        100 /var/lib/dpkg/status

I'm using Rhythmbox on a computer behind a network proxy and when I click on the "Install additional software required to use this format" button in Preferences | Music window I am informed:

"Required plugin could not be found

Python (v2.7) requires to install plugins to create media files of the following type: Vorbis encoder"

I find it highly unlikely that this is the case and therefore am assuming it's related to my network setup. I am able to browse the internet in Firefox and install packages via aptitude with my network configuration.

Please let me know what further information I can provide.

[Joshua Lock (incandescant)]

I just discovered (using apport -w) that this infrastructure is provided by the sessioninstaller package, so adding that to the "Affects".

sessioninstaller version info:
  Installed: 0.20+bzr131-0ubuntu2
  Candidate: 0.20+bzr131-0ubuntu2
  Version table:
 *** 0.20+bzr131-0ubuntu2 0
        500 http://us.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages
        100 /var/lib/dpkg/status

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[whochismo (whochismo)]

It also happens when connecting directly to internet.

There's a workaround posted here: http://ubuntuforums.org/showpost.php?p=12337687&postcount=3

[Chris Morgan (chris.morgan)]

See also https://bugs.launchpad.net/ubuntu/+source/rhythmbox/+bug/1086806 which gets the same symptoms and for which the workaround also works.

[Alberto Salvia Novella (es20490446e)]

Since this bug exhibits exactly the same behaviour as bug #1086806, it's a duplicate.