Some co-workers had problems with infrae.subversion in their buildout. I didn't get to the bottom of it, but apparently it depends on py 0.9.0 which, at least in buildout's eyes, disappeared from pypi after a recent 0.9.1 release.
If you have the same problems: a simple temporary fix is to put the next url in your buildout's "find-links" section:
My name is Reinout van Rees and I work a lot with Python (programming language) and Django (website framework). I live in The Netherlands and I'm happily married to Annie van Rees-Kooiman.
Most of my website content is in my weblog. You can keep up to date by subscribing to the automatic feeds (for instance with Google reader):