Download this file to get Poser 6 ONLY materials for Numinous. These use 8-bits jpgs instead of 16-bits pngs for the displacements; the effect on the displacement will be coarser but you will avoid the problems that Poser 6 has reading pngs.
To use these, unzip the file into your runtime, then convert the png files in the Runtime\Textures\Arien\ankh folders to jpg. Conversion can be done via any image manipulator program, including Photoshop, PaintShopPro, or even free programs like IrfanView or GIMP. Use materials as usual.
You can download the materials from here:
Poser 6 ONLY materials