Hey googlers looking for tech-support:

I was trying to install various packages (emacs, etc) from universe on Ubuntu Gutsy (7.10), and I kept getting weird segmentation faults (Setting up emacsen-common (1.4.17) Segmentation fault). Turns out that the problem was that my server was being hosted on a VPS running XEN for virtualization, and you have to first install libc6-xen: apt-get install libc6-xen

Hope this saves someone the half day that it cost me…