He is needed everywhere. In all functions where you need to specify a path to a file, you need to put a slash first:
"/Effects/_(Effect)..."
"/Characters/..."
"/Sounds/_(Sound)/..."
"/DialogScenes/..."
"/Maps/SingleMissions/..."Everywhere, except for GetMapDataPath()
I wrote before that GetMapDataPath() also causes a white screen. But if you specify the absolute path in the usual way, it works.