1.Download wow patch.          Download WoW installer

2.Update WOW patch .          Download wow patch

3.Download POLO MPQ PATCH 

Patch-enUS-9.MPQ Version v2.0 for data/enUS Download if your game path 'World of Warcraf\Data\enUS\'
Patch-enGB-9.MPQ Version v2.0  for data/enGB Download if your game path 'World of Warcraf\Data\enGB\'
Patch-deDE-9.MPQ Version v2.0 for data/deDE Download if your game path 'World of Warcraf\Data\deDE\'
Patch-enES-9.MPQ Version v2.0 for data/enES Download if your game path 'World of Warcraf\Data\enES\'
Patch-ruRU-9.MPQ Version v2.0  for data/ruRU Download if your game path 'World of Warcraf\Data\ruRU\'
Patch-frFR-9.MPQ Version v2.0  for data/frFR Download if your game path 'World of Warcraf\Data\frFR\'
Patch-esMX-9.MPQ Version v2.0 for data/esMX Download if your game path 'World of Warcraf\Data\esMX\'

put the mqp patch to the World of Warcraf\Data\enUS/engb folder and logon the game again.