Hmm, the acklog does not show anything suspicious. But I notice that the sphere seems to be at a different position in your screenshot, than in the script. A driver bug is theoretically possible, but unlikely - rendering into a cube map should be a simple process. Can you post the DxDiag 0utput?

The bone "pelvis" is there, but appears to be no parent to "Stomach". I'll look into your script in more detail.