Here's a snippet from a trac mailing list thread that hints at the problem:
Hmm. I tried, actually, putting the [graphviz] section in the main trac.ini,
but it didn't work. Maybe if I'd put the egg in the main plugins section
(trac/plugins) *and* put the [graphviz] section in the main conf/trac.ini it'd
work. (And then enable it there too).
Let's see... (goes away to try it)... nope. I get a red box with Error:
Failed to load processor graphviz / No macro named [[graphviz]] found.
Actually, never mind -- I see that trac doesn't actually load plug-ins from
trac/plugins. I don't even know how that dir got in there. It wants them to
be in the python site-packages dir. But when I put them there, I get a
message from the egg that there's no [graphviz] section in my .ini file. It
seems like it really wants that to be in the site/conf/trac.ini.
Anyway, I just put it all back into the site dir and it works fine.
