Game Not Launching Error

There's a problem we're having with the Steam build where instead of loading the new update, it tries to launch an "EmptySteamDepot". I don't know why. It's not something we've experienced before. Perhaps we missed some kind of change to the install process and now what we've normally done doesn't work any longer. We're going to work on fixing it, but I'm afraid for now the update isn't running. We'll do our best to figure it out before the end of the day! I'm really sorry for the delay. EDIT! We fixed it. There was just out-dating in our game engine that I hadn't released was not updated.