WotLK WoW Errors

[Drew2225]

I keep on receiving wow errors after downloading the worlk pack. i have checked 'read only' off of all the files as instructed before in a previous post.
This application has encountered a critical error:

The system cannot find the file specified.

Program: C:\Users\Andrew's\Downloads\Wrath of the Lich King 3.3.5a\WoW.exe
File: .\Client.cpp
Line: 3578

file: signaturefile
That is the message i receive along with a load of code! please help me someone!

[Ragaroth]

I am getting the same error.... anyone found the solution to this? thanks