Like koenh, I get an error 'Disc_SetUSB failed' while trying to start ANY game from FAT32/NTFS (installed also by Wii Backup Manager and Wiiflow). Games are finded correctly, but unplayable. When formated on WBFS, games run without any problem.
Details: Wiiflow 2.2 / system menu 4.3e / 8GB...