I couldn't get OA and Arma 2 to synch when launching and got that error CABUILDINGS in the beginning. I tried the -mod=@dayz on the target line for the shorcut and still to no avail. I spent hours and hours trying to figure out and decided hey why not try updating and installing it with SIX UPDATER. And FINALLY i got Arma 2 and OA to sync and got Dayz to start working! Just wanted to share this with you guys! But first install everything as directed in @dayz folder in OA. Launch Six updater highlight the Dayz mod on the left and hit the install/update button. Hope this helps! (this is for non steam only)