FC6 Xen can not start X

[shhgs]

My FC6's kernel is the most update version, 2.6.19-1.2911, but
whenever I boot with Xen, I can not use X . I remember when I first
installed Xen, I can start X with Domain-0. I have monitored the VMs
with virt-manager, installed the VMs with virt-install. At that time,
the kernel version was 2.6.18-1.2798, but after some updates, it
doesn't work.

My /var/log/Xorg.0.log says
--------------------------------------------------------------------
Fatal server error:
Caught signal 11. Server aborting
--------------------------------------------------------------------

Has anybody met with such problem? Have you got a solution? Please tell me.

Thank you very much.

G.S. Huang