Xen Boot Error under FC4

["Parameshwara Bhat" <peebhat@xxxxxxxxx>]

Hello List,

I was trying to learn Xen on my PIII (celeron 450 Mhz)system with 256 MB  
of RAM.I have installed xen through yum(kyum)

[pbhat@sidharth ~]$ rpm -qa|grep xen
kernel-xenU-2.6.13-1.1532_FC4
xen-2-20050823
kernel-xen0-2.6.13-1.1532_FC4

This is my grub.conf entry as given by installer.Though the package Xen is  
version 2, entris in
/boot suggest version 3.0

title Fedora Core (2.6.13-1.1532_FC4xen0)
        root (hd0,0)
        kernel /xen.gz
        module /vmlinuz-2.6.13-1.1532_FC4xen0 ro  
root=/dev/VolGroup00/LogVol00 selinux=0 rhgb quiet
        module /initrd-2.6.13-1.1532_FC4xen0.img

When I boot from this entry,XEN stops loading domain0 with the massage  
'allocated memory is too low for domain0'. I tried giving full system  
memory with ----

title Fedora Core (2.6.13-1.1532_FC4xen0)
        root (hd0,0)
        kernel /xen.gz  dom0_mem=256M noreboot acpi=off
        module /vmlinuz-2.6.13-1.1532_FC4xen0 ro  
root=/dev/VolGroup00/LogVol00 selinux=0 rhgb quiet
        module /initrd-2.6.13-1.1532_FC4xen0.img.

Could anybody suggest where's the error?

Thanks,

Parameshwara Bhat