Syslinux - Jan 2004 - boot on USB key on a PC/XP with Flonix

I/ it's very easy to boot on USB key because the Bios is up-to-date,
and install the Flonix USB Edition
with documentation of linuxdocs.tuxfamily.org/doc/ ...
and all seems good, even syslinux .exe e: with Windows XP
/PC HP pavillion ZE 4130
but in the boot, i obtain the message:

missing operating system ??

II/ other thing about a floppy, to create a boot-floppy:
vmlinux and initrd.gz are absent of distribution Flonix

thanks for all responses, even negatives
chris