Unable to generate html docs

I'm using matplotlib 0.40 from CVS and am trying to generate the html
docs as described in matplotlib/htdocs/README. This is the error I get:

$ python process_docs.py
        Converting matplotlib.cbook.html to template
Traceback (most recent call last):
  File "process_docs.py", line 20, in ?
    s = file('../docs/' + fname).read()
IOError: [Errno 2] No such file or directory:

The problem seems to be that process_docs.py is expecting to read many
"matplotlib.*.html" files, but these files do not exist.