Você precisa atualizar suas informações de repo: sudo apt-get update
Reading state information... Done
The following extra packages will be installed:
dpkg-dev fakeroot g++ g++-4.7 libalgorithm-diff-perl libalgorithm-diff-xs-perl libalgorithm-merge-perl libstdc++6-4.7-dev
Suggested packages:
debian-keyring g++-multilib g++-4.7-multilib gcc-4.7-doc libstdc++6-4.7-dbg libstdc++6-4.7-doc
The following NEW packages will be installed:
build-essential dpkg-dev fakeroot g++ g++-4.7 libalgorithm-diff-perl libalgorithm-diff-xs-perl libalgorithm-merge-perl libstdc++6-4.7-dev
0 upgraded, 9 newly installed, 0 to remove and 0 not upgraded. Need to get 10.2 MB/10.2 MB of archives.
After this operation, 28.4 MB of additional disk space will be used.
Do you want to continue [Y/n]? Y
WARNING: The following packages cannot be authenticated! libstdc++6-4.7-dev g++-4.7 g++ dpkg-dev build-essential fakeroot libalgorithm-diff-perl libalgorithm-diff-xs-perl libalgorithm-merge-perl
Install these packages without verification [y/N]? y
Err archive.ubuntu.com/ubuntu/ quantal/main libstdc++6-4.7-dev i386 4.7.2-2ubuntu1 404 Not Found [IP: 91.189.88.149 80]
Failed to fetch archive.ubuntu.com/ubuntu/pool/main/g/gcc-4.7/libstdc++6-4.7-dev_4.7.2-2ubuntu1_i386.deb 404 Not Found [IP: 91.189.88.149 80]
Failed to fetch archive.ubuntu.com/ubuntu/pool/main/f/fakeroot/fakeroot_1.18.4-2_i386.deb 404 Not Found [IP: 91.189.88.149 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
eu acabei de remover o http antes dos links
Você precisa atualizar suas informações de repo: sudo apt-get update