I've used the Plone Unified installer several times over the past months to create new sites. It's version has changed and thus some of the requirements it uses. But if I tell it to re-use the old Python, it can't find the new required zc.buildout egg version:
root@Boqueria:Plone-220.127.116.11-ex-r2-UnifiedInstaller# ./install.sh \ --target=/usr/local/zope \ --with-python=/usr/local/zope/Python-2.4/bin/python \ --password=Fnork \ --instance=newinstance \ zeo Testing /usr/local/zope/Python-2.4/bin/python for Zope/Plone requirements.... /usr/local/zope/Python-2.4/bin/python looks OK. We'll try to use it. Found existing buildout cache at /usr/local/zope/buildout-cache; skipping step. Running buildout Traceback (most recent call last): File "bin/buildout", line 9, in ? import zc.buildout.buildout ImportError: No module named zc.buildout.buildout
Parts of the install are missing. Buildout must have failed. Aborting.
/usr/local/zope/buildout-cache contains: zc.buildout-1.0.3-py2.4.egg zc.buildout-1.1.0-py2.4.egg
from old UnifiedInstaller installations. Now we need to add the 1.1.1 verison:
PYTHONPATH=/usr/local/zope/buildout-cache/eggs \ /usr/local/zope/Python-2.4/bin/easy_install \ --install-dir /usr/local/zope/buildout-cache/eggs \ zc.buildout==1.1.1
This UnifiedInstaller seems to want a 'zeo' user to run ZEO, but didn't create it for me, so do it manually, however your OS prefers; lock out the account of course.
Since the previous abortive install didn't finish, I removed the partially-crated instance directory and then re-ran the Unified Installer.
Then you can tweak the new instance's buildout.cfg -- e.g., to change the ports -- and re-run buildout.