Doesn't work - but it used to - GPG Error?

I installed an older version of Easy Ubuntu and it worked great.

Now, on a different machine I tried to get it to work and I can't.

I was trying for dvd, codecs, windows fonts, proprietary, flash, java, ati - basically all of it and I keep getting problems. Here are some of them:

W: GPG error: http://packages.freecontrib.org dapper Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F120156012B83718

also:

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/q/qt-x11-free/libqt3-mt_3.3.6-1ubuntu3_i386.deb
  404 Not Found [IP: 146.137.96.7 80]

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/g/gsfonts-x11/gsfonts-x11_0.17ubuntu4_all.deb
  404 Not Found [IP: 146.137.96.7 80]

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/libm/libmodplug/libmodplug0c2_0.7-5_i386.deb
  404 Not Found [IP: 146.137.96.7 80]

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/f/flac/liboggflac3_1.1.2-3ubuntu1_i386.deb
  404 Not Found [IP: 146.137.96.7 80]

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/libx/libxvmc/libxvmc1_1.0.1-0ubuntu4_i386.deb
  404 Not Found [IP: 146.137.96.7 80]

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/v/vorbis-tools/vorbis-tools_1.1.1-3_i386.deb
  404 Not Found [IP: 146.137.96.7 80]

The only one that appears to have worked is the libdvd (possibly) - it is checked and greyed out.

Please help - why did it work before (older version) and not now?