This sort of problem is usually caused by the mapping of the spine bones.
When you convert the character in 3dxchange have a look at the spine mapping and ensure that the bottom bone is the one that is mapped as by default it is often one of the higher ones. may be worth a try.
I took your advice and tried multiple iterations, but no success. Here are the settings that I used...
Could be something screwy on my end. I wonder if I am missing some software install perhaps? Frustrating...
Below is the video from this second attempt (actually, the third try... with multiple bone mapping retries...
Black Larry DavidGalactic BlitzBirthday Movie