Have there been significant changes to the follow curve IK feature since H17?

Working through the 'Space Girl' rigging tutorial and everything is fine until applying the follow curve IK to the twist bones (part 14).

The path normals are definitely twisting, but it's not being applied to the bones (and subsequently not to the captured geo). The twist even fails in the project example files.

The twist bone icons are updating, showing that the IK has been applied. Can't figure out what the issue might be...


--
mC