Geometry jobs should not be launched for empty tasks error

hi, i'm using unity3d 5.5.0f3 with anima2d, having this error with the skinned mesh combiner

Geometry jobs should not be launched for empty tasks UnityEditor.DockArea:OnGUI() Assertion failed on expression: 'size != 0' Geometry jobs should not be launched for empty tasks

I tried to copy the uchan character's structure, and I can't get the character in 1 draw call, the whole character have 120 tris. All the sprites are in the same atlas, and with the sprites version of the character i have just 1 draw calls. I really need a tutorial or some help with it. Thanks in advance.

Pd: sorry for my english, It's not my native language