I'm not sure what you're seeing that's wrong, but I will say that I don't see "sphereROI" set here, presumably to a radius. I think this is easier if you use 3dUndump's srad option. The class document, afni11_roi, has an example there (now on slide 30).
http://afni.nimh.nih.gov/pub/dist/edu/latest/afni11_roi/