When it comes to video cards, the most recent drivers and hardware are actually sometimes the problem with FFXI. That is becoming increasingly common with the last couple generation of graphics cards--they don't get along well with pre DirectX 9/10 content because of what Microsoft did with DirectX architecture in Vista/Win7. The last driver release from nVidia that SE tested and was flagged for being compatible with FFXI was 266.58. If you have something newer, might want to try rolling them back.

If you can provide the model of the nVidia GPU, maybe someone here got it working with that family and can provide some info on how they got it working.