Cannot start MATE Desktop [OBSOLETE]

[Cariboo]

Hi,
Just today I installed "MATE 64-bit: 776a2e820362833cdbb056c035a5f2c1" on an USB stick.It works great but I can not get to the MATE Desktop Environment.
With Synaptic P.M. I found out that the package "mint-meta-mate" - (Set of packages required to run MATE) is missing. I tried to get this package installed via Synaptic P.M. and got the message that it failed to fetch packages.
I include some screenshots to show the procedure.
What did I do wrong?
Is my sources.list OK?
Do I have to allow more of the "Other Software" Sources?

EDIT: May 24th Installation of Final Release---issue solved.

[xpander]

judging from ur screenshot about software sources, it seems that u have repos listed there as duplicate.
sources.list however seems to be fine.
something is messed up there.
what do u have in /etc/apt/sources.list.d folder?

[Cariboo]

what do u have in /etc/apt/sources.list.d folder?

etc/apt/sources.list.d folder contains two documents and no hidden files:

1) local -repository.list with one commented entry:
"# deb file:///usr/share/local-repository binary/"

2) local -repository.list.save with the same entry as above:
"# deb file:///usr/share/local-repository binary/"

[xpander]

its all fine there.
but why do u have ubuntu 12.04 'precise pangolin', recommendedd updates, important security updates, canonical partners and medibuntu.org repos as duplicate in ur screenshot of the software sources.
try to disable duplicates there and run the sudo apt-get update and try again.
that might resolve..

[Cariboo]

That's the sources.list which came with the image download. I didn't add anything.
In case you run Linux Mint 13, can you post yours