Problem with a Skies of Arcadia disc

Hi! Bought Skies of Arcadia via ebay - both discs are in good condition (disc 1 has a number of fine lines on it in various places, but no deep scratches or anything like that).

try and load the game from disc one - the disc spins for a bit, then stops and the dreamcast just goes back to the main menu.

try disc 2, it works fine (but then it asks for me to put in disc 1 - at which point, it *sounds* like its going to load the game, but then the screen goes black and doesn't come back on till i open the tray, at which point it goes back to the main menu again).

suggestions? i know DC discs can be a bit twitchy with regards marks on them, but i have a space channel 5 disc that looks like a dog ate it and it works fine.

here however, i have a (pretty good condition) disc that refuses to boot.

all my other games work fine.

/ edit - forgot to mention, sounds a bit like this guys problem:

http://www.digitpress.com/forum/showthread.php?t=106858

notice he mentions skies of arcadia too. hmmm....coincidence?

update - took the disc into Game as a last resort and got them to put it in their disc fixing machine. When i got it back, the disc was flawless EXCEPT for this one fine line from the center to the outer edge of the disc. still didn't work :(

its pretty annoying if it won't work because of the one scratch. bah.