This guide will also solve the errors such as
Waiting for server response” or “Waiting for character to create” or “Receiving Data
Servers are simply being overloaded, wait a litte or try another server. If nothing works try below.
Launch Operation Arrowhead from steam and select the option to re-install BattlEye Anti-Cheat client. If you are using retail download the latest version form http://www.battleye.com/download.html and put it in a folder named ”BattlEye” in the “Expansion” folder of your Arma2:OA main directory.
Redownload DayZ mod files and make sure you have the latest version how to Dayz Download and Install Here
If nothing works try reinstalling both Arma2 and OA.