Error #002 means that you are using the wrong IOS (often happens when using a cIOS), or an outdated version of the correct one.
The forst one can be fixed by enabling (Anti)002fix in your backup loader. The second one can also be fixed like this, but you can also install the latest version of the needed IOS. You can download the IOSs in wad form with NUS Downloader/ModMii and install them with WAD Manager or DOP-Mii.