Animation can't retarget

There is a strange problem when i retarge an animation.

Just like you see,the source skeleton is empty.
When i push the retarget button,there pop up a error message,like:

And here is some info about my skeleton:

The preview skeletal mesh is none,and you can see that the idle_Anim icon is totally black.
I can’t figure it out.
Thanks for any help.

I’m having the exact same problem. Someone please help!