1. in your wow folder rename the current battle.net.dll into battle.net.dll.bak
2. grab the archive at this address http://www.gamefront.com/files/21056241/WOW-CN4.2-exe-dll.rar , extract wow.exe and battle.net.dll into your wow folder.
that's it.
And to those who were stuck on this for days, next time take the time to screenshot or post the error log on the forum, I was able to solve this instantly after seeing the error message. All you needed was the chinese client battle.net.dll