walk behavior not working - character is missing symmetry

I'm very confused. I'm learning Character Animator and am very much an amateur, but I'm trying to get a walk behavior to work on my character. When I rig it up for head and body turner, everything works perfectly, but as soon as I add the walk behavior, it shows me all kinds of errors about missing symmetry. It says, "handle tagged as left elbow, but no other handle tagged as right elbow," which isn't the case. It also says I'm missing handles tagged as Neck and Waist, but that's not the case either. What am I doing wrong? Any help appreciated.

Files are here: https://www.dropbox.com/s/k1h6grsb16ykl76/Rig%20Practice.zip?dl=0