After looking through the Main Stats folder, I now know why the Dust Devil skillbook cannot be found.
1) The skill in SkillData.txt doesn't have a Skillbook entry listed for it
2) There is no Dust Devil (or WhirlwindStart) object in the RootTemplates
3) There is nothing in the Links folder to link the nonexistent Skillbook entry to the nonexistent Dust Devil Skillbook RootTemplate. This is why I didn't see it when I was going through the Links txt file; it's not there in the first place.
This leads me to the conclusion that Dust Devil is the only skill in the game only obtainable via Character Creation.
Which means that to fix it, I'm going to have to create my own Dust Devil skillbook object and link it properly. The potential issue I see is that the original Dust Devil entry itself doesn't list a Skillbook data, which will probably mean that I'll have to create a near-identical copy of the skill and have my Skillbook point to that instead.