Duo_R, BL is leaving out some crucial steps here.
You'll need to first compile the emulator on your Wii (the package provided is actually just source code), then you'll have to get to a command line and execute the following command:
"mednafen -f3001 -qzk1:100 -l:1024,512 -480p -framerate:100 -sound:enabled -joy:enabled -d -e -r -p /sd/<filename>.pce"