Have tried downloading from your site a couple of times and whenever I try to change the graphics settings I can't log in afterwards. It says "connecting" and then could not connect. The previous realm name disappears too. Think I can change audio settings without that happening.
Follow these steps:
1) Restart your PC
2) close your Torrent client and move your WoW folder away from your Torrent's download destination
3) now right click on WoW folder> Properties> remove "read-only".
After that you can set settings the way you like and you should be able to log in.