Notice how the output when you run apt-get update only has precise-security. I would expect there to be lines that say precise in addition to the lines that say precise-security.

Are you having trouble installing any other software? What does your /etc/apt/sources.list file look like? Here is an example sources.list file.

For dpkg-sig, you should at least have the following lines in sources.list:


If you edit sources.list, make sure you run sudo apt-get update again.