This would be better suited to facepunch.com
You cannot force a client to download lua files, that should be done automatically through the cache file (client-side lua files that is).
As for the resource.addfile, I do not know of the top of my head that much but I believe if you add a .vmt the .vtf gets added automatically and there is also no need for an add-on to handle it the lua file should do fine.
The lua script you posted above may need some tweaking to work, not sure what is happening here.
resource.AddFile('materials/Models/Weapons/v_models/M82/
M82 norm.vtf")
http://wiki.garrysmod.com/?title=Resource.AddFile
Linear Mode
