Missing Part "modelRoot"

I have successfully exported some of my models, but when I try to play any animation I get this message:

:Actor(warning): couldn't find part: modelRoot

The animation plays, but some of the models look slightly off:

The eyes look like this in Blender:

It looks like the eyes are pressed back into the head farther than in Blender even though that animation doesn’t do that in Blender. Any ideas?

EDIT: Here’s the part of my code that loads the actor. For brevity, I excluded the long list of animations.

#Load the model
self.actor = Actor(
        "body": "./player/body1",
        "head": "./player/head2"
        "body": {...},
        "head": {...}
self.actor.set_scale(.25, .25, .25)

EDIT: I fixed the distortion by re-rigging the mesh and adjusting my script slightly, but I still get the same warning about “modelRoot” being absent.