I'm trying to import some 3D geometry saved as .3DS into 3D Flash Animator 3.41

Is there a limitation to what type can be imported? When I do the Open File, I see the name of the file added under Elements, but the Geometry window is blank.

The 3DS file originated in Rhino3D--a NURBS modeler, and I exported as a .3DS mesh model. I even tried a basic sphere, but still no luck. Is this a bug, or am I doing something wrong?