That means that Xen ran 'pygrub' to extract the kernel &
initrd from the
primary disk, but was unable to find a MBR, or grub config or kernel.
Most likely cause is that the previous OS install was not successful
and thus didn't install grub/MBR in the guest.
Dan
Thanks Dan, for your suggestion.
Now, I could build the libvirt3.3 manually and install it on RHEL5 .
But still I am getting the error, while trying to start the guest.