Few questions:
1. What file type are the files you downloaded? (jpg, png, fhp, etc.)
2. Do they match the file type in the text file for the preset you want? (where it says "texture preset_#body.jpg/png")
If you downloaded fhp's, you won't be able to use these for your own presets. If the files are png's, you need to make sure the preset text file also has png's, or it won't recognize them. The names of the files also have to match.
If you're unsure, you can send the code in the text file, and we'll see if there's a problem c: