I get an error on the best WBFS manager 2011

Hello, Wii Backup Manager used to be the best wbfs manager 2011 for me because it works perfectly, until it gives me these errors:
split 0: size (-1) not sector (512) aligned wbfs
error: hd num sector doesn't match
Does anybody know how to fix it?
Thanks,
Sargent Franks
