material preset_4_bodyMatLWhat I highlighted in green and yellow are the parts that make presets possible. You need the correct image name (and extension, if transparent) and if you are specifying what body part it is, to make it easier to organize, then the green text should be your username or whatever you choose (personally, I put the character name). You must do this for every single .material code, or at least the ones you are working on/using for your preset. I would suggest copying the same name for your material, the green text, before each underscore_partmatR/L so you don't need to fuss with it later.
{
technique
{
pass
{
texture_unit
{
texture preset_4body.jpg
}
}
}
}