Got error like this, downloaded "updated" client 10hours ago and still doesnt work. WoW is up to date.
You're probably running the 64 bit version of World of Warcraft. You can check which version you are running at the log in screen. It should say x86 in the left corner and not x64. Launch WoW.exe instead of wow64.exe through the World of Warcraft folder. You may have to rename the wow64.exe to something else (like wow64wqrt.exe) Remember that Honorbuddy requires you to be logged into a World of Warcraft character. You can not start Honorbuddy before your character is online in the game world.