Error 003
Description
The so called Error 003 occurs when a Korean Wii gets region switched to a different region and then updated to 4.2 via the online update.
Technical cause
System menu 4.2x calls a new ES Ioctlv(0x45) which got added in IOS70 on other IOS' this Ioctlv always returns -1017.
If the korean-common-key is present IOS70 will return 0, which will then trigger the error in the system menu.
Fixing
There is currently no way known to fix this error. You are screwed.