if you have a cd burner, try running the scratched cd from there. burners are better at error correction (generally) than regular cd drives.
there are those that swear brasso will help a scratched cd or dvd (though there are people who also claim toothpaste does the same!)
if no other option remains, there are companies that will repair (or extract) the damaged cd for a nominal fee (about $5.00 USD).
if you have someone who can burn you a cd copy (and you can't), there is software out there that can fairly often recover the damaged areas so you can burn a playable copy. caveat - i'm not sure what type copy-protection DD uses.
lastly, i would bet that should you send your defective cd back to larian (or publishers) they would forward a workable copy to you, perhaps for a small fee (though i hate to put words in their mouths).
good luck.
