Error no suitable context info for active keying set

the bike crank rotates using i rotate. the pedals stay level.
how do i make the persons feet follow the pedals?
i tried I rotate and got the above message.
when i tried to parent to the pedals it wanted to move the whole body!
how do i set the body as bones? i am not used to these circle things.
using 2.69 and wont change.
thanks all