The IFO file to use is the one containing the main movie - in this case, VTS_03_0.IFO. I've inserted an image showing the options to use. You should end up with:
VideoFile.m2v (about 5.86 GB) Subpictures_21.sup (41 KB, you don't need the other subpictures) Celltimes.txt (1 KB)