Can't play "Bad Serial number given in Setup"?

[Squizle 0]

I installed Arma II along with OA via steam. Started the game, then started the Six Updater but when I attempt to choose a server and play it loads the game and then the game goes away and it says "Bad serial number given in Setup"

What do I need to do to get Day Z working?

[lukestephens 0]

On steam Right click arma 2 OA and go to properties then go to the Local files tab and click verify integrity of game cache

[Cloakedboltz 0]

Try to launch Operation Arrowhead once and try again.

[Monsieur Blanchard 0]

Don't worry, had the same problem when I first got Arma 2. Did you launch Operation Arrowhead once BEFORE you installed DayZ? Anyway, shut down steam

>task manager>end process> steam.exe

Once you have done that then right click on steam.exe and then select 'launch as administrator'. You only need to launch as admin the first time to get it to work. Hope I helped.

[Squizle 0]

Tried both your suggestions and it worked. Thanks a bunch friendos!