the system is down

In this case, it’s medibuntu. Or more specifically, their Ubuntu repository. As far as I can tell it’s been down for about a week now and was also down a while back for some time. For anyone who needs to utilize this pretty important resource, there seems to be mirrors out there which I wasn’t aware of. Enter Andrew’s blog post on webupd9.org:

Firstly you’ll have to find out where your Medibuntu repo is located. Run this in a terminal:
ls /etc/apt/sources.list.d/medibuntu.list

If the file exists, press ALT + F2 and enter:
gksu gedit /etc/apt/sources.list.d/medibuntu.list

If running the above command lists the medibuntu.list as not found (“ls: cannot access /etc/apt/sources.list.d/medibuntu.list: No such file or directory”), then do the following:
Press ALT + F2 and enter:
gksu gedit /etc/apt/sources.list

Then for both cases, search for the lines which point to the main Medibuntu repository, which should look something like this:
deb http://packages.medibuntu.org/ lucid free non-free
deb-src http://packages.medibuntu.org/ lucid free non-free

Of course, if you’re not using Lucid, it’s going to say “karmic” or “jaunty”, etc.
Replace these 2 lines with any of these 3 mirrors:
Mirror 1:
deb http://mirrors.ucr.ac.cr/medibuntu/ lucid free non-free
deb-src http://mirrors.ucr.ac.cr/medibuntu/ lucid free non-free

Mirror 2:
deb http://mirror.oscc.org.my/medibuntu/ lucid free non-free
deb-src http://mirror.oscc.org.my/medibuntu/ lucid free non-free

Mirror 3:
deb ftp://ftp.leg.uct.ac.za/pub/linux/medibuntu/ lucid free non-free
deb-src ftp://ftp.leg.uct.ac.za/pub/linux/medibuntu/ lucid free non-free

If you’re not using Lucid, replace “lucid” in the above lines with “karmic”, “jaunty” or whatever Ubuntu version you’re using.