Trying to determine why pytz installed by easy_install was broken, I located the
following problem:

When setuptools extracts a tarball source dist to install it, it silently drops
any tar members which are neither files or directories. The problem is in
archive_util.py which specifically tests "if member.isfile() or
member.isdir():". I am uncertain why it would try to do this, but it is fatally
incorrect to do so when the software being unpacked includes symlinks as a
functional part of its sourcecode, as pytz does.