Are you sure? Because I updated my Wii a couple of days ago to buy some stuff from the Wii Shop Channel.
BTW - Confirmed working on PAL Wii by me -
Wiikey 1.9s, firmware 3.2E.
No patch applied to the ISO, just burn and play.
My thoughts by the 20 minutes I played: A suprisingly nice music game. It doesn't try to immitate Guitar Hero, but instead offer something new and interesting to the genre. Controls are pretty percise, and the covers are nice(30 songs overall, 5 different versions for each one). You should at least give this one a try if you're into music games.