Install DVD problems

I am trying to install Windows 7 via Boot Camp on my mid-2010 15" MBP. During partitioning, I get the error that tells me to backup, erase, and restore Macintosh HD. I researched this and that seems like following the instructions is the only way to get around this (let me know if I am wrong please), and I started to do this. I have an external HD, which I backed up to via Time Machine.

I hunted down my install DVD, and tried to boot to it. I tried holding "C", and I tried holding "option", but both times, it would read the disc for roughly 30 seconds, and then eject it. This is the install DVD that came with my Macbook, it has 10.6.3 on it. It has no visible damage, so it seems like it should be working. It also ejects itself when I try to put it in with OS X booted from Macintosh HD, but I am not sure if this is normal or not.

Does anyone know how to fix this?

FYI, everything is updated.