i looks like your adding your 3D object to the wrong thing.
var ciao:first = new first()
addChild(ciao);
that code will do nothing because your adding a 3D object
into flashs default 2D scene. to render your object in 3D
with papervision, try somthing like this...
var ciao:first = new first();
scene.addChild(ciao);
to see anything in papervision3D you need 3 thing.
Scene, where the objects are in 3D space
Camera, your viewpoint for seeing the scene
Viewport, where the actual graphics get rendered in flash.
you might wanna read a few pv3d tutorials
and wrote this tutorial for using the geomclassexporter a while ago
hope that helps!