do-release-upgrade - Could not determine the upgrade

Question

Edit: Answer at bottom, I'm leaving the question untouch to keep all elements that might match someone else's search.

So, I've read about the issue (here, here, here and here) but could not find the help I needed.

It's happening on a server I run for personal usage, so it's not really well maintained. It's running Ubuntu 12.10 (told you!) Server on which I've installed a KDE desktop that I can connect to remotely using X2Go.

Through SSH, I tried do-release-upgrade which resulted in the error in the title.

At this point, I opened the /var/log/dist-upgrade/apt.log file which ends with

Can't guess meta-package
Your system does not contain a ubuntu-desktop, kubuntu-desktop, 
xubuntu-desktop or edubuntu-desktop package and it was not possible 
to detect which version of Ubuntu you are running. 
Please install one of the packages above first using synaptic or 
apt-get before proceeding. 

Easy enough... But:

$ sudo apt-get install kubuntu-desktop
Reading package lists... Done
Building dependency tree       
Reading state information... Done
kubuntu-desktop is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

I also tried

$ sudo dpkg --configure -a

followed by

$ sudo apt-get install -f

as advised in one of the answers linked above, just in case, but nothing changed/happened.

---

Then I tried to look for Broken like advised in one of the cited thread and got this :

$ grep Broken /var/log/dist-upgrade/apt.log
Broken cups-filters:amd64 Conflicts on ghostscript-cups [ amd64 ] < 9.06~dfsg-0ubuntu4 > ( text )
Broken php5-common:amd64 Breaks on php-apc [ amd64 ] < 3.1.13-1 > ( php ) (< 4.0.0)
Broken php5-common:amd64 Breaks on php5-suhosin [ amd64 ] < 0.9.33-3build1 > ( php ) (< 0.9.34)
Broken php5-common:amd64 Breaks on php5-xdebug [ amd64 ] < 2.2.1-1 > ( php ) (< 2.2.2)
Broken python3-pykde4:amd64 Depends on python3 [ amd64 ] < 3.2.3-5ubuntu1.2 -> 3.3.2-14ubuntu1 > ( python ) (< 3.3)
Broken libsnmp30:amd64 Breaks on libsnmp15 [ amd64 ] < 5.4.3~dfsg-2.5ubuntu1.1 > ( libs )
Broken software-properties-kde:amd64 Depends on python3-pykde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python )
Broken python-kde4:amd64 Depends on sip-api-8.1 [ amd64 ] < none > ( none )
Broken libfftw3-double3:amd64 Breaks on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs ) (< 3.3.3-1)
Broken apport-kde:amd64 Depends on python3-pykde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python )
Broken ubuntu-release-upgrader-qt:amd64 Depends on ubuntu-release-upgrader-core [ amd64 ] < 1:0.190.8 -> 1:0.205 > ( admin ) (= 1:0.190.8)
Broken libmuonprivate1:amd64 Depends on software-properties-kde [ amd64 ] < 0.92.9.3 > ( kde )
Broken muon-notifier:amd64 Depends on ubuntu-release-upgrader-qt [ amd64 ] < 1:0.190.8 > ( admin )
Broken gtk2-engines-pixbuf:i386 Depends on libgtk2.0-0 [ i386 ] < 2.24.13-0ubuntu2 -> 2.24.20-1ubuntu1 > ( libs ) (= 2.24.13-0ubuntu2)
Broken muon-updater:amd64 Depends on libmuonprivate1 [ amd64 ] < 1.4.1-0ubuntu1.1 > ( kde ) (= 1.4.1-0ubuntu1.1)
Broken userconfig:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python ) (>= 4:4.7.0-0ubuntu2~)
Broken muon:amd64 Depends on libmuonprivate1 [ amd64 ] < 1.4.1-0ubuntu1.1 > ( kde ) (= 1.4.1-0ubuntu1.1)
Broken krita:amd64 Depends on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs )
Broken muon-installer:amd64 Depends on libmuonprivate1 [ amd64 ] < 1.4.1-0ubuntu1.1 > ( kde ) (= 1.4.1-0ubuntu1.1)
Broken usb-creator-kde:amd64 Depends on usb-creator-common [ amd64 ] < 0.2.40ubuntu2 -> 0.2.50 > ( admin ) (= 0.2.40ubuntu2)
Broken apturl-kde:amd64 Depends on python3-pykde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python )
Broken jockey-kde:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python )
Broken plasma-scriptengine-python:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python ) (>= 4:4.6.80)
Broken kde-config-touchpad:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python ) (>= 4:4.5)
Broken kubuntu-desktop:amd64 Depends on software-properties-kde [ amd64 ] < 0.92.9.3 > ( kde )
Broken php5-ps:amd64 Depends on phpapi-20100525 [ amd64 ] < none > ( none )
Broken php5-imagick:amd64 Depends on phpapi-20100525 [ amd64 ] < none > ( none )
Broken php5-mcrypt:amd64 Depends on phpapi-20100525 [ amd64 ] < none > ( none )
Broken php5-imap:amd64 Depends on phpapi-20100525 [ amd64 ] < none > ( none )
Broken php5-memcache:amd64 Depends on phpapi-20100525 [ amd64 ] < none > ( none )
Broken ia32-libs-multiarch:i386 Depends on gtk2-engines-pixbuf [ i386 ] < 2.24.13-0ubuntu2 > ( graphics )
Broken kubuntu-notification-helper:amd64 Depends on ubuntu-release-upgrader-qt [ amd64 ] < 1:0.190.8 > ( admin )
Broken libfftw3-double3:amd64 Breaks on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs ) (< 3.3.3-1)
Broken ubuntu-release-upgrader-qt:amd64 Depends on ubuntu-release-upgrader-core [ amd64 ] < 1:0.190.8 -> 1:0.205 > ( admin ) (= 1:0.190.8)
Broken plasma-widget-facebook:amd64 Depends on plasma-scriptengine-python [ amd64 ] < 4:4.9.5-0ubuntu0.1 > ( kde )
Broken krita:amd64 Depends on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs )
Broken plasma-scriptengine-python:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python ) (>= 4:4.6.80)
Broken ia32-libs:amd64 Depends on ia32-libs-multiarch [ amd64 ] < none > ( none )
Broken ia32-libs-multiarch:i386 Depends on gtk2-engines-pixbuf [ i386 ] < 2.24.13-0ubuntu2 > ( graphics )
Broken kubuntu-notification-helper:amd64 Depends on ubuntu-release-upgrader-qt [ amd64 ] < 1:0.190.8 > ( admin )
Broken libfftw3-double3:amd64 Breaks on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs ) (< 3.3.3-1)
Broken ubuntu-release-upgrader-qt:amd64 Depends on ubuntu-release-upgrader-core [ amd64 ] < 1:0.190.8 -> 1:0.205 > ( admin ) (= 1:0.190.8)
Broken plasma-widget-facebook:amd64 Depends on plasma-scriptengine-python [ amd64 ] < 4:4.9.5-0ubuntu0.1 > ( kde )
Broken krita:amd64 Depends on libfftw3-3 [ amd64 ] < 3.3.2-3.1ubuntu1 > ( libs )
Broken plasma-scriptengine-python:amd64 Depends on python-kde4 [ amd64 ] < 4:4.9.4-0ubuntu0.1 > ( python ) (>= 4:4.6.80)
Broken ia32-libs:amd64 Depends on ia32-libs-multiarch [ amd64 ] < none > ( none )
Broken ia32-libs-multiarch:i386 Depends on gtk2-engines-pixbuf [ i386 ] < 2.24.13-0ubuntu2 > ( graphics )
Broken kubuntu-notification-helper:amd64 Depends on ubuntu-release-upgrader-qt [ amd64 ] < 1:0.190.8 > ( admin )
Broken plasma-widget-facebook:amd64 Depends on plasma-scriptengine-python [ amd64 ] < 4:4.9.5-0ubuntu0.1 > ( kde )
Broken ia32-libs:amd64 Depends on ia32-libs-multiarch [ amd64 ] < none > ( none )

Notice that kubuntu-desktop is in the list. Not sure what to do with that...

As a side note, here is the list of PPA or thrid-party repository I've on this server

chris-lea-node_js-quantal
dropbox
google-musicmanager
guilhem-fr-vsftpd-quantal
newrelic
nginx-stable-quantal
nilarimogard-webupd8-quantal
tuxpoldo-btsync-quantal
webupd8team-sublime-text-2-quantal
x2go-ppa-quantal
x2go-stable-quantal

Which leaves me with a couple of questions:

• Am I supposed to delete all these packages by hand ?
• Will the update go through correctly after that ?
• Should I plan a whole afternoon to fix issues after the upgrade in order to get back a working configuration ? (Like: X2Go, KDE workspace etc...)

---

Edit:

The actual problem was the unreachable ubuntu mirrors due to the EOL process. As pointed in the comment, fixing the source.list helped. See this answer for ways to fix the source.list.

Thanks to saiarcot895 for pointing me in the right direction!