How do I solve this Nvidia driver download error?
Solution 1:
Okay, I found the solution. Here's exactly how I did it. If you have a similar issue, your results may vary.
Go into Synaptic and completely remove all Nvidia related packages, plus Jockey. Make sure to "completely remove", not just uninstall.
Re-install only jockey-common, jockey-gtk, nvidia-common, nvidia-current, and nvidia-settings. If it tries to auto-select any other packages, unmark them. Seriously.
This is critical: After Synaptic has installed the selected packages, reboot once. Not rebooting at this point will cause failure later. At least, it did for me.
After rebooting, open System Settings->Additional Drivers. At this point, I saw different options than the screenshot in my original question. I went with the one marked "Recommended". Select activate, and reboot again.
After rebooting, you might not see much change. For me, I wanted to enable dual monitors but at this point only one monitor was on. Open up Nvidia-settings, and the second monitor is now recognized. Enable and configure as you see fit.
My graphics now seem to be working as they should.
I hope this information helps others with similar problems.
Also, this is how my restricted drivers interface now looks:
Solution 2:
Go to the Package Manager, search for the "nvidia-current" package and install it. That's basically what's the Additional Drivers program is doing.