Link to video is you need to re-install Dayz Control Center, and what you must do: http://youtu.be/erWuerV2HBs
If you are having a version conflict then download this small batch file I created if you are trying to connect to your game. Also share this with your friends so they can connect as well.
Just to play Dayz: http://www.justallinone.com/files/Pla…
Extract the batch file into your ARMA2 game directory.
For those who are running the Steam version, and can’t get it to run, try this since it has worked for other people…
…Copy the AddOn folder from your Arma2 install folder to your Arma2 Operation Arrowhead folder.
UPDATE: If you get the player, and password is invalid.
Follow these steps. (1) Go to your ARMA 2 directory, and delete @dayzcc, and @dayzcc_config folder. (2) Start your Windows Task Manager, and stop both HTTP process’s. Stop the 2nd one first, then the HTTP which is left. (3) Stop the mysql process in your task manager as well. (4) Go to where you installed the Dayz Control Center software. Start setup with admin rights. Do a FRESH Install, Just select NEXT, DO NOT select already have a database running, and PLEASE watch the video again