there is no problem. this happens sometimes, its normal. dont worry about it.
i could explain why this happens but you wouldnt understand anyway.
IOS15 is downgraded from original IOS15-v523 to IOS15-v257. then pimp my wii uses this IOS15-v257 to perform minimal install. this IOS15-v257 does not have proper permissions to perform all the functions pimp my wii needs to perform the steps in manual install. this is the reason for this step, Once Minimal is done, Exit Pimp My Wii. so then pimp my wii can reload and use a different IOS.
minimal does install a properly patched IOS36-v3351. this patched IOS36-v3351 has proper permissions to perform all the functions.
i dont know if you noticed in the hack my wii thread, member Wateva tries to say that pimp my wii can not install IOS249. this is not true. the problem is with the IOS15, he was trying to install using this IOS and not a patched IOS36.
when the guide is followed as outlined it works correctly.