Pak File Loader Plugin

So I did this:
Root: ‘/MaterialLibrary/’
Content Path: ‘…/…/…/MaterialLibrary/Content/’

Now when I am checking if the directory:

‘/MaterialLibrary/AutomotiveMaterials/Materials/Exterior/BrakeRotor’

exists ,it returns false.

Also,I am not sure if and when I have to user function “TryConverrFileNameToLongPackageName()”

Now I tried to check the dir for existence with the following path:

‘…/…/…/MaterialLibrary/Content/AutomotiveMaterials/Materials/Exterior/BrakeRotor/’

And now it finds it. But it still fails to load the material from there.

Also,do I have to load AssetRegistry?