Cannot edit sources using synaptic

[Andreas Schallenberg]

I cannot edit the /etc/apt/sources.list using synaptic packet manager.

When I select "" I get a dialog saying that the packet sources have been changes and I should click on "reload".

Original German text:
"Paketquellen wurden geändert

Die Informationen der Software-Paketquellen haben sich geändert. Um die Änderungen zu übernehmen, klicken Sie bitte auf "Neu laden". "

This happens every time. The terminal says:

Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 104, in <module>
    app = SoftwarePropertiesGtk(datadir=options.data_dir, options=options, file=file)
  File "/usr/lib/python2.7/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 134, in __init__
    proxy = bus.get_object("com.ubuntu.SoftwareProperties", "/")
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 241, in get_object
    follow_name_owner_changes=follow_name_owner_changes)
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 248, in __init__
    self._named_service = conn.activate_name_owner(bus_name)
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 180, in activate_name_owner
    self.start_service_by_name(bus_name)
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 278, in start_service_by_name
    'su', (bus_name, flags)))
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1

The machine is a Strato virtual server running Ubuntu 12.04.2 LTS (GNU/Linux 2.6.32-042stab055.12 i686).

# uname -s -r -v -o -i -m -p
Linux 2.6.32-042stab055.12 #1 SMP Wed May 23 16:07:36 MSD 2012 i686 athlon i386 GNU/Linux

My sources.list:

# See sources.list(5) for more information, especialy
# Remember that you can only use http, ftp or file URIs
# CDROMs are managed through the apt-cdrom tool.

deb ftp://ftp.stratoserver.net/pub/linux/ubuntu precise main restricted universe
deb-src ftp://ftp.stratoserver.net/pub/linux/ubuntu precise main restricted universe

deb ftp://ftp.stratoserver.net/pub/linux/ubuntu precise-updates main restricted universe
deb-src ftp://ftp.stratoserver.net/pub/linux/ubuntu precise-updates main restricted universe

deb ftp://ftp.stratoserver.net/pub/linux/ubuntu precise-security main restricted universe
deb-src ftp://ftp.stratoserver.net/pub/linux/ubuntu precise-security main restricted universe

#deb http://mirror.kolabsys.com/pub/ubuntu/incoming/kolab-2.4 precise release updates
#deb-src http://mirror.kolabsys.com/pub/ubuntu/incoming/kolab-2.4 precise release updates

deb http://mirror.kolabsys.com/pub/ubuntu/kolab-3.0/ precise release updates

# apt-cache policy synaptic
synaptic:
  Installiert: 0.75.9ubuntu1
  Kandidat: 0.75.9ubuntu1
  Versionstabelle:
 *** 0.75.9ubuntu1 0
        500 ftp://ftp.stratoserver.net/pub/linux/ubuntu/ precise/universe i386 Packages
        100 /var/lib/dpkg/status

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1153267/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Launchpad Janitor (janitor)]

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