Mental Ray Rendering - Geometry Not Moving!?!?

Hi Everyone.

PLEASE I really need some help with this one.

I am having very strange problems rendering in mental ray. My character's eyes are parented to his top head joint (have tried just grouping also) and in the scene when his head turns his eyes go with it. When I render a single frame the eyes are in the correct possition but as soon as I try to batch render the eyes are in the correct possition for the first frame only and do move with the head. This happens no matter what frame i start rendering at. The first frame is in the correct posssition but then the eyes do not move.

The problem only seems to exist when i use mental ray and happens no matter what settings I have in my render globals, default, custom, production, raytracing on/off, final gather etc etc.

Have tried simply creating a new sphere and grouping it under the head to see if it is a problem with my geometry but the exact same thing happens again when I Batch rendered.

Is anyone has any ideas I would greatly appreciate some help. I am truelly stuck with this one.

thanks

Jen

Bake the sim to keys.