I just tried to install epydoc as you suggested under Windows 7. First it said it couldn't find Python in the registry. I checked: the registry contained Python 2.7.1. I upgraded to Python 2.7.2, and that problem disappeared. I'd encourage you to expand that error message, e.g., "cannot find a current version of Python in the registry" if it's too hard to include version numbers in the error message.
With Python 2.7.2 installed, I got "Could not create ... epydoc-py2.7" -> "Could not set key value Python 2.7 epydoc-3.0.1" -> 'Could not set key value "C:\Users\sgraves\pgms\Python\Python2.7.2\Removeepydoc.exe" -u; "C:\Users\sgraves\Python\Python2.7.2\epydoc-wininst.log"'. See attached.
Then I tried "epydoc --pdf dirname -o dirname_docs" at a command prompt per "http://epydoc.sourceforge.net/manual-usage.html". I got, "'epydoc' is not recognized as an internal or external command, operable program or batch file." I'm not surprised, because I could not find an epydoc.* executable file anyplace. It's possible that it is hidden someplace where I can't find it and it's not in the Windows 7 path, but I searched for it and couldn't find it. This may be me misreading the documentation, but I was unable to take the next step. Thanks. Spencer Graves