FeralHeart+ is having some problems lately - like the one you are experiencing. I suggest looking through the forums once more from the 'search' box above. There, you'll probably find an answer. I'm pretty sure I've seen a 'How to fix the black screen in FH+'' thread. Otherwise, it's best to just stick with the normal version of FH.
Click this to fix the black screen if the character creator's background (and/or) is black and all you can really see are your character and the icons.
I will get an image of how else to fix this for you soon. Edit: Sorry, I just realized there was another reply now, because my browser doesn't allow the ''Warning - while you were typing a new reply has been posted. You may wish to review your post.'' popup. I don't know why.