[Mike Mattera]

If you Analyze and click the part, does the whole thing light up. Does it say it's a solid. You Can bring in an IPT as surfaces. You dont want that.

What toolpaths are you trying to do?
If your trying to rought or finish you have to tell it your picking from a solid so It can cross section it. If you have cross holes or openings in the solid, the cross section wont come out right and you'll have errors (like the one's your getting).

I might have a v9 video around somewhere that shows how that works.

Mike Mattera