Hi Bruce
I think you're running in to some kind of a limit on vertex numbers or numbers of parts on an imported polygon here. I tried splitting your shapefile up, and it's just feature number 9 that's showing the problem, and splitting that feature into two separate polygons meant that both imported OK. I'll refer this one for more investigation.
On the subject of the error messages, we're aware that the error messages are currently not very informative in many cases, and are working to improve this in a future release. I'll update this thread when I find out more on the issue, and make sure the help is updated with more information too.
