This probably wont happen to anyone else but incase it does you can follow the instructions to fix it. The reason this happened was either a person or program set permissions of the /usr/sbin folder to not be overwritten. This is generally a good idea for security reasons that way programs cannot overwrite the important files. But also a problem when you want to update files in the /usr/sbin folder. What you could do is always use the chattr program to set the permissions back after updating what you need to but it might be more of a pain then it is worth.
Anyways good luck.