How do I import texture directories (and sub-directories) associated with FBX files? Thanks
Unity will automatically import any compatible asset files that are placed in the "Assets" folder, so all you should need to do is make sure that the FBX file and its associated directories are all saved together inside the Assets folder of your project.
If you have done this, and you're still having problems, please give a little more detail in your question so that we can find the problem!