Darkedge, thanks, yes that's the kind of testing I'd usually do,  good common sense stuff...

but it doesn't apply in this case because the modeling app is not a general purpose modeling app. It only generates heads, and it starts with it's own mesh, and you cannot import an object. 

I'm getting help from the app tech support, but we haven't made any progress yet, it really should not be happening. Next step: reinstall.