This is a v7 3DM file, bt MOI only supports v5

 From:  Michael Gibson
10388.21 In reply to 10388.19 
Hi James,

re:
> so a 3dm file can be either triangle mesh or CAD surfaces and solids?

Yes a .3dm file saved by Rhino can contain a variety of different kinds of data, including triangle meshes or CAD surfaces and solids.

MOI is focused on only the CAD data.

- Michael