Hi,
Please double-check your Library Browser > Preferences > Options - for the best performance, by default, the "Add 'maps' folders to 3DS Max texture paths" feature has both the "Only Built-In Library ("Forest Library")" and "Exclude network paths" options checked - disabling these should do the trick (the Forest Pack plug-in will also search in your "custom libraries" and should be able to add them automatically).
I hope that helps.
Best regards,