It almost sounds like you are inside your network not outside.
Thats what I thought - but he says he is trying to come from another city and his vlc box is in the router dmz, etc.
"but since I don't have admin, I can only use portable apps."
Huh??? So your vlc server serving up the files is at home, so what would that have to do with admin rights - I would assume you have admin rights at home.. Why don't you just bring you movies/media on a usb disk and plug it into your work computer to watch via sure a portable media player or even the built in media player
So home box is in the dmz of your home router, but don't show it listening on 8080 - was that output from your work or home vlc server box?
Work - is work just a home type router as well for their internet connection. Most work networks don't allow nonstandard outbound, ie for example 80, 443, 21 might be allowed but 8080 would be blocked outbound from the work network.