I failed to package up the Zip and Tar correctly for Radiant 0.5.2. They each included Rails 1.1.5 instead of 1.1.6. I've repackaged the files and they should be ready for download as soon as they propagate to the appropriate download servers.

Since Rails 1.1.5 has a major security vulnerability it is recommended that you upgrade immediately if you installed from Zip or Tgz.

To download, see:
http://rubyforge.org/frs/?group_id=1337