jkw109 is right.

I burned 7 coasters before choosing disk-at-once in Nero 6 (XP SP2).

By default Nero burns the image as track-at-once.

I don't know how Nero burns - but TAO from cdrecord does burn perfectly good CD's that you can boot from and install from - they fail the media test on IDE cdrom machines, but pass on SCSI cdrom machines. It's an ide-cd bug in the kernel.

Of course you should burn DAO because the media test then (usually) passes - but if you did burn TAO you don't necessarily need to reburn, at least with cdrecord (I don't have nero and can not test there)

Do you mean when we first boot off the CD we type in ide=nodma linux mediacheck?Its that what we are supposed to do?Please reply ASAP!Ok?

I haven't tried that but it supposedly works.
If you get media check error - just see if you can install anyway.

If you have access to cdrecord - try burning with

cdrecord -dev=/dev/hdd -speed=16x -v -pad -dao fiename.iso

obviously /dev/hdd should actually point to YOUR burner, and speed=16x is whatever speed you want, and filename.iso is the iso image.

Burning that way, at least for me, makes CD's that pass the media check.
The -pad may not be necessary, but I'm positive the -dao is.

But if you don't specify those burn options, it very likely will install just fine anyway - it just won't pass the media test. I did several installs of FC3 from such CD's before I figured out the -dao trick. Since I test add-on software, I do a lot of installing of fresh systems ...