[Calypt]

I've had similar problems with other games but not NWN with bugs. In the end I had to uninstall the game and then re-install it. Though I don't recall ever hearing about this bug/problem with the game.

Perhaps, certain parts of your game file has become corrupted. Try uninstalling and then reinstalling the game. Your saved games should still be there when you reinstall just make sure that you don't delete all games files (IE Saved games) when it ask if you want to.

Other than that I don't know what else to say. I hope this helps.