My Centos was fresh from the Live DVD 64bit. Selinux was disabled.
The only item I could see different were around the following.
As CentOS 6 is based on RedHat 6, and RedHat has dropped support for Xen in version 6, we need to get Xen from a third-party repository. We can enable the repo as follows:
yum install http://au1.mirror.crc.id.au/repo/ker...6-3.noarch.rpm
I think the xen release is a different version than that installed in the Howto?