I have tried this NTSC game burnt onto a DVD-R disc on a pal machine with Rev 9 and Rev 13b and though both load the game with the gamma loader , they both freeze at the same place with an error.
The Wii is on version 3.2 (which may be the problem)
The error has the tiger woods loading background on the screen and has a black box with a green surround and white writing that reads :
The Game Disc could not be read.
Refer to the Wii Operations Manual for details.
I dont have a USB loader on this wii and no access to one from here so i cant check any more but the disc didnt work on it so it may be some new protection.