This might help:
Solution one: Go to Local Disk (C:)\FeralHeart\Presets and search for the preset file you downloaded. If you see something like 'Username_#(1)' [Or 2, 3, 4..etc..] then just Right click the file, select 'Rename' and delete of the (1) [Or 2, 3, 4... you get the idea]. Then restart FH again!
Solution two: Go to Local Disk (C:)\FeralHeart\Presets and search for the preset file you downloaded. Ask your friend if they have any capitals in their name if you don't see any. Example: You see bigbangtheory but it's actually BigBangTheory. If that is the case then Rename the file to the correct user name and restart FH.
Solution 3: If you're seeing your friend's old preset instead of the new one, all you need to do is Replace the old one with the new one instead of having a duplicate.
Hope this helped a little.
Can they noot see the preset at all as if they never got the download or do they see entirely white? If it's entirely white, that's a different problem. It doesn't matter what it's saved as, as long as it matches the .material file before you export it. For example:
If it says texture preset_5body.png in the material file, you have to save it as preset_5body.png.