You don't actually say what the error is, so it's a little tricky to determine what the problem is.But now I get an error when I try to go the SystemMenu. But that error is displayed for 5 to 10 seconds and I get the main screen as if I just powered up the Wii. If there is a small fix, please let me know. Thanks.
And for the other questions the answers are Yes, Yes and Yes.
Use a backup loader such as perhaps Neogamma.