Error with rig editor, comes up with a error message when I try to make a custom rig?

So this error pops up when I try to make a custom animation for a goose rig, it says: the following parts are affected by multiple Moter6D's: Torso, Head, Torso, Head, Torso, Head. I don't understand the parts only have one.

I had this problem too. I solved it by using a Rig Editor plugin to easily see what is going on with the motor6D's, because I am lazy. What I did was place the motor6D's from the chest or center of the rig to the limbs / shoulders and from there to the elbows and so on, instead of for instance, from the elbows to the shoulders to the chest. I honestly don't know if this is your problem, but I believe this will make it stop showing that error message. Sorry if this explanation makes no sense.