Hello. I was wondering if someone could help.

I am working through 'Learning Maya 7 Foundation' and in the chapter that I am on I am trying to animate a walk cycle. After I put my character into the start pose. I try to set a keyframe by pressing S, but I get this error message:

// Error: animCurve creation or connection failed for attribute robot:robot.lHeelControl_translateZ //

It doesn't seem to stop me from animating the rest of the walk, but when I open up the Graph Editor to adjust the curves I can only see the curves for the pelvis (I think...)

I have the character set turned on. When I don't have it turned on, l I don't get the error message, but still can't see the curves.

Any help would be greatly appreciated!