There seems to be something wrong with your install of either Sphinx or numpydoc. If it's missing completely, the traceback says:
Could not import extension numpydoc (exception: No module named 'numpydoc')rather than complaining about "Directive". Possibly a mixup with versions? Also note that you're saying that you see numpydoc in the sphinx directory - did you mean in site-packages instead? That's where it should be: