The scene is very simple: A figure, a paraboloid mirror and a transparent plane with refraction.

The result is a broken or yagged figure, even with refraction index set to 1.00 the distortion is present.

I am using Poser6, I don't know if I have to setup something else or is a Poser6's bug or in Poser 7,8,9 this still happens. Later I shall try to render this same scene with LuxRender.

In this image I have used refraction index = 1.00

Stupidity also evolves!