That looks very good, better than what I had with my RITEK D01s.
The first 4 GB are still in layer 0 where the beam doesn't have to go through the semi-reflective layer, so it's the easiest part of the disc to burn. When the drive gets to the layer switch, it begins hunting for the layer 1 track, trying to focus on it. From your description, it sounded like it failed there, after repeated attempts, probably involving optical pickup movement.
There are two things that might help your next burn, slower speed and not getting too close to the outer edge.
First, slowing down to 2.4x, even if the drive offers you 4x burning, is a good idea, given the first failure.
Second, burning with DVD Decrypter. I don't know where Nero places the layer break [who knows, it may burn to the end of layer 0, like CD-DVD Speed]. DVD Decrypter always places the layer break squarely in the middle, so, if your disc is not the full 8.542 billion bytes, you won't get too close to the outer edge, where vibration is higher, and the track may be harder to focus on.