Checking TGA's in my model folder, I think that some of the texture files needed for the "Dark Upholder" are:
GenUTTO.tga
GenUTTO_d.tga
U_TUTTO.tga
GenORRETTA_01.tga
GenORRETTA_01b.tga
GenORRETTA_01bd.tga
Check if you have them, though it may need some more that I couldn't identify. I'm sorry I can't be more specific, but my knowledge of these questions is almost nil. If you don't have them I can send them by mail if you want.
This is how the Upholder looks in my game:
Then I have this, which is the last version I downloaded (the one on canarb's site):
No idea of wheter it needs external textures or not.