Problem with SuperDrive?

I found that my MacBook Pro (late 2008, 2.4Ghz) model had this problem a few months ago, but I brushed it off, since the problem didn't really affect me that much.

My SuperDrive's problem is that it can't seem to be able to burn CDs or DVDs. It can read CDs or DVDs perfectly fine, and I know this, because I've ripped songs off of CDs many times and I can play Call of Duty: MW Campaign mode, which requires the game disc to be inserted.

But, no matter what I try to do, I simply cannot get my MBP to burn discs. Whenever I put a CD or DVD in, my computer simply does not recognize that I've entered a blank disc, giving me the prompt " Please insert a blank disc, then press OK" (or something along those lines).

I'm under a 2 year AppleCare warranty. My obvious first question is, could it be some kind of problem with the configuration? I sincerely doubt this, but in the small case it is a software problem, under what should I be checking?

My second question is, if Apple recognizes it as a problem that is covered under AppleCare, then how long will it take for them to get my MBP repaired? Will they simply give me a replacement or will it be something where I have to leave it overnight or for a few days?

Thanks beforehand.