I've followed the excellent tutorial found here:
http://wiki.contribs.org/PXE_booting_to_BARTPEI've created a BartPE ISO using a Windows Server 2003, Standard 32bit SP1 installation.
I did not download the SP1 file but took the required files straight from the installation disk.
This might be the bit where it went wrong, but I doubt it because the installation disk is SP1 too.
Then I expanded the underscored files, created the winnt.sif file and confirmed my directory tree is the same.
During booting it does find and download the startrom.0 file but then it errors out with "TFTP download failed"
Some forums suggested the NTLDR could not be found but I've verified it's there as shown in the example tree structure.
Any hints?