Looking at your spline object, I see there are two points on the pipeline occupying the same coordinates. If you make a spline object with no overlapping points, free envelope, it should have a nice cross-section. But when I import a wavefront.obj exported from Poser as vertex object, then try to save the Carrara file with the vertex object, it says "unknown error" and fails to save. Mac OS X.2.6, C2. And the progress bar pops up a few minutes later, saying 90% saved, where it stays indefinitely. Importing a Poser obj as facet meshes is not sufficient for several operations, and it crashes when trying to convert facet meshes to a vertex object.