Packages: "task-xfce4" and "task-xfce4-plugins" are NOT on Repo in this moment.
Yes, they are.
The was on Repo yesterday, but they aren't on Repo now.
I think that's due some package-upgrade... Soon you will have these packages (updated, obviusly) from Repo, in Synaptic, I think.
Synaptic > Settings > Repositories >>> click your active repo entry > look at the Section(s) line > you should see main updates nonfree kde4 games xfce4.
I suspect you do not have xfce4 on that line. Add it and click ok. Reload.
Neal i absolutely agree with you ... Monsee it tells me you are also not installing the latest iso ... as it contains the correct repo sections .... please use the latest 2012 iso ....
When I write, yesterday, the 2 packages aen NOT on Repositories (I check 7 different Repos and don't see the two packages).
Before (about one hour before) the 2 packages ARE into Repo (in all Repos).
After (3 hours after) the two packages ARE into Repo (I check only Heanet and GARR, bau in other Repo they are too, I think).
The absence was temporarily, but I don't know b why. Some "re-disolocation", I can suppose...
Later more (about 6 AM, here, in Italy), I try to install the 2 packages in my Phinx installation (Phinx 2011, of course), but fail.
NOT the installation was failed: simply, the installation require to install a lot of packages (tetex, etc...), creating the same situation that before...
So, I chose to not make installation, for that moment.
I would try to install the XFCE desktop (using Synaptic) when is installation don't give problems like re-installation of tetex & Co, if they give problems for Kile, etc...
In that moment I cannot install Texlive due the lacks of a library ("libpoppler.so.13": I had see it (or similar: maybe can be: libpoppler13) BEFORE that moment and I am seeing it NOW [I am with PCLinuxOS, in this moment, but not the Phinx installation], but I cannot see the "libpoppler.so.13" package in the needent moment, yesterday. Not on GARR and not on Heanet Repo, in my Synaptic).
Different story for Phoenix installation: in Phoenix installation I have installed texlive and the "fonts extra" related (these fonts extra I had successfully installed in my Phinx installation... but texlive package, not: I cannot install the texlive package in Phinx installation, this morning).
No problems for LXDE and LXDE-mini installations (I have Kile and LyX, etc... and Texlive, here). In Phinx I have problem. But NOT in other versions.
Not at all: I tell you all this to give help to solve all this updating issues. I'm sure that all will be solved good, at last.
UPDATE: I have installed now Phoenix Edition (the last ISO) 32 bit. My System is now in english language (I have not translated it, yet, due the fresh installation).
When I open Synaptic the first time, it tell me to uninstall -really!- all XFCE desktop and some other package...
So, I have attempt to update without uninstall the XFCE desktop environment totally... I had selected one to one te single updates and mark by my hand. In this way, update go. But, after, Synaptic claim the same that would uninstall about 50 (or more: the "gtk-doc" package was uninstalled too) packages... including the whole XFCE desktop environment.
I had agree, at last... and it uninstall me all desktop (I can see my desktop, now, only because I haven't rebooted yet).
From Synaptic, in this moment, I attempt to install the "texlive" package... but Synaptic answer that it's impossible, due the "libpoppler.so.13" package lack... An I don't see -really- that package, now, in Synaptic. My Repository, now, is Headnet.
I have unistalled -for my decision- "tetex" also (and all related packages). But, after, I cannot install the "texlive" package due the loss of the "libpoppler.so.13" package.
Now, I have only the "texlive-mfwin" package and the "texlive-fontsextra" package... and no other LaTeX related packages.
After, I go to install the "task-xfce4" package. The "task-xfce4-plugins" package is not installable because the lack of the "wheater plugin". In this moment I have not Thunar (uninstalled), so I will attempt to work for "task-xfce4-plugins" package after Thunar reinstallation (I hope).
The "task-xfce4" package installation require the reinstallation of ALL the tetex packages that I had unistalled before... So, I have tetex and all his friends again, but cannot install texlive!... Yuppi!

Extra good-new!... Also the "task-xfec4-plugins" package installation failed at all, because the ATP translation give me an error message.
I have removed (in: /etc/atp) the "preference" file before attempt, but the "task-xfce4-plugins" installation don't work the same...
So, I have deselect the "wheater plugin" eand the "task-xfce4-plugins" packages and have installed all others packages (that's work).
I have the XFCE desktop, now, but... if I click to "Mark all Upgrades" in Synaptic... Synaptic claim to uninstall again all XFCE desktop and the Tetex related packages...
It's appear like a "looping", an incomprehensible goose-game...
Add-Locale don't work too... and refuse to translate my System to italian language, because it claim -before all- the XFCE desktop environment total uninstall.
I have my System in italian language, now.
To have it, I had uninstall all the XFCE desktop environment... After it, Add-Locale work to tranlate in italian language my System.
After tranlation, PC was reboot (by System) and when I attempt to login, I have no more a desktop (no more XFCE)... No desktop, nothing.
But I chose don't close a little windows that tell me a message about the session duration (10 seconds). And, for time the windows stay open, the session also is open!
So, I click on screen "by right push" with my mouse and select to open Synaptic. It open (I give the root password) and I was able to reinstall the XFCE deskto for the 4rd time in brief hours...
Now, I have italian language and I have a desktop, but Synaptic claim me to uninstall the XFCE desktop environment all!...
I think there is -somewhere- some error, because it's very strange my incomprehensible issue!