When you export SAT out from ViaCAD, make sure you set it to an older version like ACIS V8 or V4 - that should help avoid it writing out specialized types of ACIS objects that the MoI importer does not understand. The MoI importer only knows how to handle regular NURBS surfaces, if it runs into something that's stored as a special "vertex blend surface" for example it won't know how to recreate that type of object.

- Michael