Orbiter failed to set up the transparency

[S Murder]

I keep getting the above message. I've looked around and it appears that I have to change my settings from vesa to nvidia drivers, but how do I do that? I've been wandering around the web interface for about an hour and can't find that option. I did see an option to switch my video device from a standard card to a geforce or TNT2, but it didn't change anything. How do I switch the driver?