[ANSWERED]Mists of Pandaria not starting

I recently downloaded mists of pandaria from your website. Each time I attempt to start the game I am being shown the same message.

"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"

Please help me.

Right click on the game folder, properties and uncheck the read only box.