Not sure whether SPHARM-PDM actually works on Windows, I have not tested it. Has anyone else been able to get SPHARM-PDM to run on Windows?

I have used SPHARM-PDM on both Mac and linux platforms without problem and I suggest you try those. Alternatively you could be able to get it to run through cygwin on a Windows machine.

Btw, Slicer extensions get compiled for all platforms automatically, but if a tool compiles it does not mean it actually works.

Best regards
Martin