I'm a newbie here and having trouble getting off the ground. I've tried two separate times to download the game to my Mac (with solid internet connections each time, as suggested in the FAQ) and each time I go to launch the game, I get the dialog box I'm attaching a screenshot of here. In case the attachment doesn't work, the dialog box says, "The Walking Dead" is damaged and can't be opened. You should move it to the trash.
I'm running Mountain Lion (10.8.2) on a new Macbook Air, which appears to satisfy all the system requirements. Any help anyone can provide would be most appreciated.