wubi installaion misses some modules of grub needed to work with Xen

[tapas_mishra]

Here is a situation I installed Ubuntu on a friends laptop using Wubi in his Windows 7 drive.I have installed and things worked by now perfectly without any problem.We are trying to set up a Xen (virtualization)environment in this laptop.After setting up every thing cleanly.When I needed to boot with following grub entries


menuentry "Xen Linux 2.6.32.27" {
insmod ntfs
set root='(hd0,2)'
loopback loop0 /ubuntu/disks/root.disk
set root=(loop0)
multiboot /boot/xen.gz
module /boot/vmlinuz-2.6.32.27 dummy=dummy root=/dev/sda2
loop=/ubuntu/disks/root.disk ro console=tty0
module /boot/initrd.img-2.6.32.27
}

I got

error:file not found.
when booting and

error file not found
error unknown command 'multiboot'
error unknown command 'module'
error unknown command 'module'


Now to dig this issue further I reboot the machine and go to grub command prompt and manually pass on each of the above parameters which you see in the grub entry when I reached

grub> insmod multiboot
then I got following message on screen

error:file not found.

It looks like this grub setup has just enough modules to use loopback file on ntfs and directory grub in
C:\ubuntu\install\boot\grub is completely empty.
Since the ACTUAL /boot directory is on the loopback NOT ntfs (hd0,2). Therefore any attempt to read any files from (hd0,2) simply wont work, cause there's no file there.

I necessarily need to use
insmod multiboot and command multiboot and module which are available in grub on a normal install which is done without using Wubi.But since the laptop is not mine so I am not allowed to partition it and have to make it work in this situation only.
While a normal Kernel is still booting? How can I get module multiboot in this Wubi based install?