dump_session() seems to fail when used with ipython notebook set up for inline plots. When the %matplotlib inline magic is used you get a traceback resulting in
PicklingError: Can't pickle 'RendererAgg' object: <RendererAgg object at 0x42a2bb8>
and when using the --pylab=inline option at start up you get a traceback resulting in
PicklingError: Can't pickle <class 'matplotlib.axes.AxesSubplot'>: it's not found as matplotlib.axes.AxesSubplot

Using Dill 0.2a.dev, ipython 1.1.0