Can't run WoW

Hello, I've intalled some weeks ago the wotlk version and it all worked fine. Now I installed Pandaria and I can't even run the game, it opens a window that says "Data/enGB/wow-update-enGB-18273.MPQ: World of Warcraft can’t make a required change to an archive file. Be sure you have write permission for the World of Warcraft folder or try running the game in administrator mode. For more information, see: https://battle.net/support/article/6910".
What do I have to do now?

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"