I bought Neverwinter Nights for my father to play on his Ubuntu 13.04 system and wanted to get it working on my own machine before trying on his.
After installing, I was having trouble with the whole screen being black and unresponsive to keyboard and mouse input. The only option was running it in safe mode (a safe mode shortcut is created by the GOG installer).
I found an extremely simple fix for this while trying to disable the intro videos. Disable the intro movies.