Modern loaders prefer a single .wbfs file on a FAT32 drive. If your file is a raw WBFS image (not a file with .wbfs extension), you need to convert it.
Use WiiBackupManager:
Assuming you have a legally backed-up copy of Just Dance 2 and a softmodded Wii, here is how to handle this specific file. Just Dance 2 -WBFS- -SD2E41- -NTSC- -wiiGM-
wiiGM (Wii Game Manager — a PC tool for converting/transferring Wii ISOs to WBFS)