I originally thought my burner was faulty (LG 4082B), but I decided to give reinstalling Nero a try. I did a clean reinstall and tried it again, success! My settings were 2x write and burn-at-once off.
So when I thought everything was fine again, I went to burn another video, this time at 2.4x write and burn-at-once on. Now I get the same error message that I had before I uninstalled Nero, it says:
Unable to Create Disc Structure.
Could the culprit be the burn-at-once? or could it still be the drive?