Wii ROMs on Dolphin 5.0

I've tried downloading several different games (Smash Bros. Brawl, Pokemon Battle Revolution), for the most recent version of Dolphin, and once I extract the disc files, my pc simply tells me the files are corrupted, so I can't play them. I have had no troubles with Gamecube roms, such as Smash Melee, but Wii games are causing me problems.