Comment 1 for bug 145058

This is not a bug report. If you happen to install ubuntu while you were in alstralia you choose in the first couple of prompts in installer your country and it from there adds it to /etc/apt/sources.list.
Im not sure hwer eyou are right now but open /etc/apt/sources.list in your favorite editor using sudo or gtksudo If using gedit or kate or kedit use gtksuod or kdesu (gnome or kde) but you wan to open it as sudo and you will see lines like deb http://au.archive.ubuntu.com/ubuntu/ gutsy multiverse atleast i think its au but anyway remove the au and use the country code for wher eyou live now or even pull the "au. out of it totally so it reads like
deb http://archive.ubuntu.com/ubuntu/ gutsy universe and you would also remove gutsy and replace with the version you are on. do this for all of the lines that have the country code in there (the security repos dont use country code, than run sudo apt-get update than open update manager or use sudo apt-get upgrade. The GUI update-manager using whatever repos are in the sources.list file
Please report this to launchpad answers at https://answers.edge.launchpad.net/ubuntu/+source/update-manager/