That's similar to what happened to me - I was in a hospital with a guest access. RedSingularity gave me these to fix it:
sudo rm /var/lib/apt/lists/ca.archive.ubuntu .com_ubuntu_dists_natty_main_binary-i386_Packages ..then sudo rm -r /var/lib/apt/lists/* -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/346386 Title: [MASTER] Update fails with invalid package files with "Encountered a section with no Package: header" -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
