I also created a fresh domU using the wiki article located at http://wiki.centos.org/HowTos/Xen/InstallingCentOSDomU
After this since i have to use lvm, i created a new lvm volume, mounted the file, copied the first partition contents to the lvm volume. Now when i try to boot the lvm volume, it gives me the below error
mount: could not find filesystem '/dev/root'
Setting up other filesystems.
Setting up new root fs
setuproot: moving /dev failed: No such file or directory
no fstab.sys, mounting internal defaults
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init.
unmounting old /dev
unmounting old /proc
unmounting old /sys
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!