error code 0x80020063

That is a generic verify error basically saying that the write did not compare to the original properly.

While I love Apple products I have to say I have always had problems burning CD/DVDs on all my Macs (6 of them) over the years until I bought a good external burner.

I tried various media brands with mixed results, even replaced the super drive in one Mac, still no joy. Then I bought an external LaCie drive and now I don't make any more coasters.

I was burning CD's at 2X speed with few errors but a DVD you could forget it. And burning a CD any faster would almost never work.

With my LaCie I burn at max rate and often it ends up around 15X speed and have not had one single failed burn since then. I have probably only burned 60 disks but still I had never burned that many in a row in my life without many failures.

Personally I just think the drives Apple uses are junk.

One other thing if you are using toast is the be sure buffer underun is on.