Thanks for re-making the Lightwave demonstration, noviski. It captures [generally] what I've done in the past with jointed robotic figures. I guess what I was hoping for when I posted this original question was: "Is there anything in Carrara 4.0 that is a small miracle, and will make this 'walking business' easy?" And the answer appears to be: 'No."

I've posted a re-make on a little technique that I've used on jointed figures...in the side view. The red posts are foot positions: the left foot toes at a back post, and the right front heel at the next post forward. The short yellow posts are midway positions and show the height of the pelvis at its lowest point. The red post also marks the pelvis at its highest. [These are not to scale in this pic.] Using this to set up the first couple steps ensures that the feet will not be sinking down into the floor, and the foot will not slide as long as it's centered on its post. Then you can duplicate/repeat keyframes and continue the walk as far as you want.

I found this URL on the Eovia site. It's a C4 tutorial [probably] and [probably] has sound, but I can't get the sound to play. I've asked Eovia [via e-mail] about the sound, but have gotten no reply. See if it will play for you.

http://www.eovia.com/demos/carrara/ik_walk.asp