Why won't bootable CDs work?

[Machina]

OK, lets get the facts straight.

1. I have an original WindowsXP Pro CD. It works. It boots, and lets me install WindowsXP Pro on a formated hard drive .

2. Windows does not use any CD protection (or so we think), besides a CD-KEY.

3. When I make a copy of my ORIGINAL WindowsXP Pro CD with either Alcohol 120% or BlindWrite - I can BOOT into Windows Installation process, BUT I get an i386 error. This happens ALL THE TIME with a copied CD, and NEVER happens with the original CD.

4. If am to use NERO and manually adjust all the settings (such boot sector) and make a copy of the original CD - it works JUST AS GOOD as the original CD, WITHOUT any errors.