Fat Sorter 1.0.4 seems to run as designed on my 64-bit PC running Win 10. The program does not allow for any custom sorts. Just alphanumeric with ascending; no option to save a custom sort. It works very fast & efficiently. No errors.
If I ever learn that Fat Sorter 1.0.4 is no longer available on the Softpedia website, I could try to make it available on my WordPress Blog (along with my FirmWare 1.28 download page).
Best Wishes with your AGPTEK A26 player.