Richard60 tried to construct mathematical nodes to emulate the Color Ramp node.  You should be able to find them in the Freestuff section.  I was too intimidated to try it out back then; I never bothered to dedicate the time.

Depending on how the ColorRamp node is incorporated into the shader, you might either eliminate the node entirely or substitute a math node.  The primary function of the ColorRamp node is to modulate the intensity of a given map or alter the color gradient range.  In Poser 13, there is partial functionality, depending on how the dark and light pointers are placed.  Too close together, and the node would begin showing strange random color shifts.  I rely on that node for ambient occlusion Superfly renders, and I'm glad I reported it in time to have it corrected in P14.