On my Fedora 10 box, I get this:
$ dot -V
dot - Graphviz version 2.16.1 (Mon Jul 7 18:20:33 UTC 2008)
So I'm using the monkeypatch below to get all working:
import re
from epydoc.docwriter import dotgraph
dotgraph._DOT_VERSION_RE = \
re.compile(r'dot (?:- Graphviz )version ([\d\.]+)')
