Extra ring on the CD?

[Xagest]

I've been trying to burn the recent release of Space Channel 5 part 2, with no luck. The cdi file burns fine, no errors at all. Same with the unzip. But the disc, for one reason or another, doesn't work.

I looked at the bottom of the disc, and saw something really weird. There is a ring of unwritten disc on the border where the Audio boot data seperates from the Game data. What exactly is this? And how do I get this game to work?