@estherau: I've been through everything in the V5I Mat editor (including colour, bump, reflection....) checked them all.
And the Mat for the forearm WAS copied from one of the other "limbs" mats (in fact they all were - they're all clones - I don't trust anything). I'd be a lot less worried if the problem had shown up between different areas of the texture map (eg between "Torso" and "Limbs") - but this is all in the same area..
The mats for the forearm, the arm and the hand are identical. That's the 1st thing I checked. That's also why I posted - I don't quite understand what's going on..

@Morgano: I agree. I think there's something happening. The Poser 6 example is extremely subtle, but I couldn't get PSP9 to show things more clearly than I could already see on he screeen.. - will try harder soon.. But the fact that I can see it (even if I can't graphicically show it yet) in P6 seems to prove that it' something underlying within the V4 mesh as provided.

OTOH - I'm not too worried. I'd always intended to put "Bracers" on the arms, which would totally hide the problem anyway:-)). But it's an intellectual problem that will continue to intrigue me..

Cheers,
Diolma

But (again OTOH), Maybe I should check everything again.. tomorrow..

(Which reminds me - must change my avatar...- too realistic.)