Processing dependencies for twistedcaldav==0.1.dev
Searching for ZopeInterface>=3.1.0c1
Best match: ZopeInterface 3.1.0c1
Downloading http://www.zope.org/Products/ZopeInterface/3.1.0c1/ZopeInterface-3.1.0c1.tgz
Processing ZopeInterface-3.1.0c1.tgz
Running ZopeInterface-3.1.0c1/setup.py -q bdist_egg --dist-dir /tmp/easy_install-KEKTYw/ZopeInterface-3.1.0c1/egg-dist-tmp-sJkNDR
zip_safe flag not set; analyzing archive contents...
zope.testing.doctest: module references __file__
zope.testing.doctest: module MAY be using inspect.getsourcefile
zope.testing.doctest: module references __file__
zope.testing.doctest: module MAY be using inspect.getsourcefile

Installed /private/tmp/dst/lib/python/zope_interface-3.1.0c1-py2.4-macosx-10.4-ppc.egg

Because this distribution was installed --multi-version or --install-dir,
before you can import modules from this package in an application, you
will need to 'import pkg_resources' and then use a 'require()' call
similar to one of these examples, in order to select the desired version:

    pkg_resources.require("zope-interface")  # latest installed version
    pkg_resources.require("zope-interface==3.1.0c1")  # this exact version
    pkg_resources.require("zope-interface>=3.1.0c1")  # this version or higher

error: Could not find required distribution ZopeInterface>=3.1.0c1