Are you seeing other UI elements, like character portraits and text field borders?
There is an engine-level bug that makes certain interface elements not appear after the game starts. This includes dialogue choices, so when you encounter the first choice, you can't proceed beyond it. It seems like that's what you're experiencing.
Bad news is we tried everything we could think of to get rid of this bug and nothing works. It looks like the engine developers are the only people that would be able to fix this.
Good news is this seems to happen mostly on the first time the game is run after being installed. Try again a few times and see if the problem persists. All players that reported this issue so far were able to resolve it simply by restarting the game.
If you've encountered a different bug to what I described, it's best if you send us an email to support@digitalseductions.com with a detailed description of what is happening and we can work on solving it.