Your does indeed support the resolutions that the game runs at, so that's not the problem. The game doesn't support any of those widescreen resolutions that you've tried, though. It might support 1600x1200 through the .ini hack, but usually the highest it supports with the patch is 1280x1024 or 1280x960, so I'd give those three a try. You can also play around with the Nvidia control panel's flat panel scaling settings.
Otherwise I haven't a clue why it won't run fullscreen.