To fix your problem this is all you would need in the sources.list you posted.
deb ftp://ftp.it.debian.org/debian/ testing main contrib non-free
deb http://security.debian.org/ testing/updates main
deb http://www.deb-multimedia.org testing main non-free
The issue you have is because you had part of the ftp.it.debian.org line in your sources.list twice.
Also due to Debian's new policy you don't really need the deb-multimedia line unless you are specifically wanting Windows codecs.
EDIT:Grange beat me to it. I wouldn't include the deb-src lines unless you want or need to download the source as well as the installable debs.