It looks like a setuptools issue.
If you're using an older version of setuptools, (prior to 0.6.28) it doesn't understand .dist-info and so it doesn't see the six package as installed.
It looks like a setuptools issue.
If you're using an older version of setuptools, (prior to 0.6.28) it doesn't understand .dist-info and so it doesn't see the six package as installed.