Nostalrius Begins - Quality wow vanilla realm (1.12)

Ive downloaded the file and when i go to loggin through the vanilla wow it just says my account is wrong or something.

http://www.reddit.com/r/Nostalrius/comm ... _up_guide/

i read that file and found out i need to eddit the realmlist.WTF folder but it is locked! i cannot edit the folder or delete the folder.

The folder is locked. how do i unlock it?