For what it's worth I had the same problem (I also have a Lite-On DVD RW) and, noticing that many others had as well, I tried the LiveCD install instead which resulted in other errors. However, I had noticed that my DVD ISO was not showing up properly in Windows XP; it basically appeared as being completely empty, even though I was able to boot the initial Fedora installer from it.
I decided to download the ISO again, verify the SHA1SUM, and re-burn it. Once I did that, I noticed that the DVD now showed up in XP properly. And when I booted from it, I got the expected media check option, etc. and I am now happily running Fedora 7! I'm not saying yours is the same situation but, in my case, I believe the problem was a bad DVD burn, bad media, or bad download. I would try to burn another DVD just in case.
Hope this helps,