$ hg help subversion abort: No such file or directory: /usr/lib/python2.6/site-packages/hgsubversion/help/subversion.rst Reproducible: Always
I can confirm this bug.
For some reason the help file is not being included in the release tarballs. Reported upstream.
I've sent a pull request to upstream. Since there's not much we can do here other than waiting for a new release, closing.