dot warnings when build docs

I am trying to do a clean rebuild of the docs, and am seeing warnings
from dot/digraph when I do the latex part. Looks like this is coming
from the inheritance diagram support:

jdhunter@...606...:doc> dot -V
dot - Graphviz version 2.14.1 (Fri Sep 7 12:22:15 UTC 2007)

# here is the build output
dumping search index...
build succeeded, 4 warnings.
Sphinx v0.3, building latex
trying to load pickled env... done
building [latex]: all documents
updating environment: 0 added, 0 changed, 0 removed
processing Matplotlib.tex... index users/index users/intro
users/installing users/pyplot_tutorial users/navigation_toolbar
users/customizing users/index_text users/text_intro users/text_props
users/mathtext users/usetex users/annotations users/artists
users/event_handling faq/index faq/installing_faq
faq/troubleshooting_faq faq/howto_faq faq/environment_variables_faq
devel/index devel/coding_guide devel/documenting_mpl
devel/release_guide devel/transformations devel/add_new_projection
devel/outline api/index api/matplotlib_configuration_api api/afm_api
api/artist_api api/figure_api api/axes_api api/axis_api api/cbook_api
api/cm_api api/collections_api api/colorbar_api api/colors_api
api/pyplot_api api/index_backend_api api/backend_bases_api
api/backend_gtkagg_api api/backend_qt4agg_api api/backend_wxagg_api
glossary/index
resolving references...
writing... Error: <stdin>:1: syntax error near line 1
context: digraph >>> inheritance <<< s {
WARNING: /home/jdhunter/mpl/doc/index.rst:None: (WARNING/2) 'dot'
returned the errorcode 1
WARNING: unusable reference target found:
https://sourceforge.net/project/admin/?group_id=80706
Error: <stdin>:1: syntax error near line 1
context: digraph >>> inheritance <<< s {
WARNING: /home/jdhunter/mpl/doc/index.rst:None: (WARNING/2) 'dot'
returned the errorcode 1
Error: <stdin>:1: syntax error near line 1
context: digraph >>> inheritance <<< s {
WARNING: /home/jdhunter/mpl/doc/index.rst:None: (WARNING/2) 'dot'
returned the errorcode 1
Error: <stdin>:1: syntax error near line 1
context: digraph >>> inheritance <<< s {
WARNING: /home/jdhunter/mpl/doc/index.rst:None: (WARNING/2) 'dot'
returned the errorcode 1
done
finishing...