Problem was that for some reason, this Mod does not install into the same place as every other mod that Knossos manages.
Yes, Wings of Dawn is a total conversion (aka TC) meaning that it doesn't need retail FS2 installed (i.e. it's completely free, as opposed to needing to buy a $10 copy of FS2 from GoG/Steam). It's the same as Diaspora in this respect. If you were to install either as a FS2 mod they probably won't work due to conflicting or additional FS2 files.
There's discussion in progress about Knossos making it clearer what is a TC vs a MOD, however RL means that the coders involved haven't been able to donate enough of their spare time to make these changes.