I used to get that with Poser objects which have a preview shading zone.  Try bringing the figure  into the texture room in Carrara and see if it has a preview zone.  If it does, try changing it to a simple color like red or black and see if he is visible.  Incidentally, when you just bring the actors and scene elements into Carrara from the content tab instead of importing it, then if you create the scene on Carrara, this no longer happens.  No idea why.  This is one of the main reasons I don't use Poser anymore unless I absolutely have to.