I second what Harley just said about quality media.
You can try A106 firmware, there's a thread in the LG sub-forum about it somewhere. I'm betting, as suggested, that CMC MAG AM3 just isn't supported.
Try and swap them with someone for media that's supported in your LG?
BTW, Datawrite Titanium (and other Datawrite discs) tend to come from all sorts of different manufacturers, so you can never be sure if the discs have the same MID.