RTL8168 driver not initialising

[AndyDeSheffield]

Hello Everyone
I'm doing something a little different booting IPXE from Windows XP with Grub4Dos as a bootloader. This is done using ipxe.lkrn as a menu entry in the Grub4Dos menu file and by passing an initial config file to ipxe through an initrd command

title ipxe
kernel (hd0,0)/ipxe.lkrn
initrd run.ipxe

and with run.ipxe containing (amongst others)

#!ipxe
dhcp

When booting like this (rebooting straight from xp and directly into ipxe )
the dhcp command fails with a timeout although ifstat shows the link open
However if I do the following
. Turn off the dhcp server
. reboot XP but press F12 during the boot process and select network boot
. let it fail
. turn the device off completely
. re-enable the dhcp server
. turn it on and through grub go straight to ipxe without ever letting XP boot
then dhcp gives me an address and everything works fine
Finally If I replace XP with Windows 7 there are never any problems going from Windows to ipxe. Everything inc the dhcp command works fine

I'm concluding that the XP driver somehow initialises something in a bad state that the Ipxe Realtek driver doesn't put back but the embedded ipxe stack on the network card does.
Anyone ever seen this or do you have any thoughts or ideas?
Thanks a lot
AndydeSheffield