You’re mixing two different filesystem contexts – Dir$ and FileLen commands are OS type commands, and the server!! sytax is Notes/Domino network pathing.
If you’re looking at Word .doc files, you can’t do it over the network via Notes protocols, you’d have to use UNC pathing/mapping at the OS level (\server\dir\file.doc). If you’re accessing the file locally (which I assume you are since you’re using LocalHost), just drop the LocalHost!! from your path.