If you see something like this when you render your mhx import, it is because Manuel has changed the face numbers of the base mesh. I will fix the problem soon, but it will reappear every time the topology of the base changes.
To have full control over the looks, the mhx assigns materials to each face. E.g., the diamonds are shadeless with alpha = 0, to make sure that not only are they transparent, but also cast no shadows, don't affect raytracing, etc. When face numbers change, so do the material assignment.
Besides, something has happened to the skin shader. Are there any texture gurus out there who can point out which settings should be changed.