In SBP, the textures are part of the effect of some presets (some will have a rough texture, some will have a shiny reflection, etc.) I have also noticed, occasionally, that even if the bmp/jpg image for a particular preset was in the folder, it still asked me to find it manually. If your folder for Environments and textures is empty, I guess you can remove it and see if the presets still work. If it has some files, you can test by copying that folder somewhere else (safe) and putting the files in the other folders. If it works, fine. If not, you can just put the folder back where it was.