[syslinux] pxelinux and 2.6.9 kernel parameters

[scott domars]

I am using RHEL4 with kernel 2.6.9. I can load this on my hardware by
passing the following kernel parameter: memmap=496M at 16M, and it loads up
and runs OK. If I do not use this parameter, I get a kernel panic.
When I try to load the same software onto the same hardware using PXE, I
add the same parameter on the server's
tftpboot/pxelinux/pxelinux.cfg/default file: 
append  initrd=some_file.gz memmap=496M at 16M

On startup, the slave machine negotiates the transfer OK. The kernel
transfers. The initrd transfers. The kernel uncompresses the image OK
and boot starts. The kernel panics and dies with an error like "ram
image not found at 0"

Where has the uncompressed image gone to? Is there an offset at play
here? Is pxelinux not compatible with (older) EISA based machines?
My hardware is an old Compaq Proliant 5000 server. The need for a kernel
memory parameter is well documented. Please see www.cpqlinux.com.
Thanks for any help.