I suggest you play .23c. It looks like you have too less ROM on your graphic card. Compared with .22, .23 loads very much faster.When I'm starting the game by loading a save, the screen sometimes stays black. That happens sometimes, theres another problem that happends much oftener: While loading th save, i have to wait serval minutes until I can see the map, the units, the citys, etc. Moving a Unit takes serval minutes, because it freezes for a while before the Unit moves.
That means, I have to wait 20 minutes to three Units. Many other actions in game are getting extremly time-killing. If I try to shut Civ4 down after this to get back to the desktop, I often get a Runtime error. In version 0.20 and 0.21 it was possible to load the save again and again until it works. That (nearly) doesn't work anymore with version 0.23.
Also remove options you don't really need such as low movements, action play e.g. You should optimize the options, this will help. Good luck!