PyPRP2 has been moved to GitHub, where it will live happily alongside our other CWE-related projects. The new repository is available at http://github.com/H-uru/pyprp2.
If you want to continue to use Mercurial to access the rcode, you can use the hg-git extension to access the GitHub repository.
The repository at zrax.net will remain available in a read-only form for the foreseeable future, but no new development will take place there.