No answer box to complete mission

I've just purchased and installed the game, started the first mission, got past the initial video, found the hidden message in the postcard but have no box in which to put the answer in.

I have reinstalled the game but it has made no difference is there a known issue or other steps i can take to try to rectify this?

Here is a screenshot of what i see.

 

if you click on the rectangle (marked red) you can input your answer there