You may try to play media file through ftp as well
SMB share works very well but I have to have my pc on for streaming video. So I tried ftp it works like a charm and just turn on the external hard drive hooked to my router through its usb port. Set ftp up with no authentication and disable wan access in my router. Edit ftp.conf of Mplayer and leave user and password blank. It takes few tries to connect. It turns my Wii into a wireless media player.
My router is an Asus WL520U running Tomato with usb mod firmware. Your hard drive has to be formated as fat32 to be mounted on router.
This is a great place to mod your wii. I did not pay any attention after hard mod my Wii few years ago with D2C chip. It is so lucky for those who waited for soft mod became available. I had to solder 30 more wires, man what a job it was.