Done a bit of reading...what the issue is, is 23.976 in itself is not DVD compliant. You can encode to 23.976 fps and have it work for DVD....BUT, when you encode, you have to activate 2:3 pulldown...you wind up interlaced video that is 23.976 fps, but when transferred to DVD, plays at 29.976 fps, because the frames within the video have been flagged to repeat in a certain order, so that it plays at 29.976.
It would appear that you did a straight conversion to 23.976, with no pulldown involved, so the video, as is, will not work in a DVD player. There is a program that can take a video running at 23.976 and do pulldown on it, but I need to do some more reading...