I don’t have a clear answer, but have been faced with this sort of thing on several occasions.
What’s different here with Skimmer Metal or even Skimmer Metall is that the author seems to have included some slightly different versions and tests in this folder. So maybe there are some that aren’t quite the finished article.
Things to try…..
1. Ignore the file and see if you have an instrument that works.
2. Point Kontakt in the direction of a similar file (Skimmer_Metall.nkr) and see if you have an instrument that works.
3. Copy the Skimmer_Metall.nkr file, rename it Untitled.nkr then point Kontakt in the right direction and see if you have an instrument that works.
4. Use the provided wav samples and build your own instrument.
Note: if you are happy with any of the results, use Save as…
5. Ignore or even delete that nki altogether and try the next instrument.
6. Wait for Anders to reply, as he does frequent this forum.
7. See if you can contact Anders another way (via social media ?)
8. Hope someone else gives you a workable solution.
All the best.