I am having this problem as well.
This is Melody for Aiko 3. I don't know of a way to get her into CC3 since she is older than V4/M4, so I am using 3DX.
I have had this problem with a couple of other figures.
I have tried changing the bones around, but nothing seems to be working for Melody.
If I use the DAZ Preset, I get the green ball in the upper left, but the convert button won't light up.
If I try moving the bones around I get a red ball in the upper left, and the convert button won't light up.