Help I cant login!

I download mop today.But i cant open its 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 should i do?Help

1) close your Torrent client and move your MoP folder away from your Torrent's download destination
2) now right click on MoP folder> Properties> remove "read-only"