Slipsteaming SP1 on XP Corporate Edition

Here's the give:

I've tried slipstreaming SP1a into XP Corporate and all goes well. I burn it with Nero 6, do a verify and all is well.
Start to set up a system for my company with the new cd and I get an error message as follows:

The following value in the .sif file used by setup
is corrupted or missing.
Value 0 on the line in section [SourceDiskFiles]
with key "SP1.cab "
Setup cannot continue. To quit setup press F3

I've created this a couple of times using the instructions on this site and burned it on new media each time. This happens with each attempt.

What's up? I can't figure this one out.

 

Have you looked at any other guides to creating Slip Streamed CDs?

http://www.ultratech-llc.com/KB/?File=BootCD.TXT