The last update to 1.2.4 or whatever, the hotfix for it too, screwed me.
I couldn't play since the update, through six, commander, steam or any of them.
Ended up rolling back my DayZ version to the one before the update (was playing fine on friday) just to get some game-time. I will now be keeping a backup of every update. Through all this drama though, between me and the two blokes I usually play with we all end up with a different problem needing a different fix... Such is alpha.