Below is a snippet from a python class I created that accepts some esriJSON to create & manipulate some arcpy geometries and returns them as esriJSON. The last line is crashing ArcCatalog 10.1 (with the "Please tell ESRI about this problem" dialog). The "pou" is a fully-functioning arcpy.Polygon object (other than the JSON bit)--I can see its WKT, length, and area; and do other polygonal things with it like buffering & such. Does anyone out there have any experience with this sort of thing?
pou = tracedLine.buffer(bufferMeters)
fPoint = tracedLine.firstPoint
lPoint = tracedLine.lastPoint
bPod = arcpy.PointGeometry(fPoint,self.sr)
self.OutputPodB = bPod.JSON
self.OutputPodE = ePod.JSON
self.OutputPou = pou.JSON ## This crashes Arc (even though all other arcpy.Geometry methods work fine on the pou object).