Why I am not able to start X server on "XenCenter" guests ?

Issue

• Required package groups "GNOME Desktop Environment" and "X Window System" are installed on RHEL5 XenCenter guest.
• When trying to start X server on this VM, getting fatal Error (Connection reset by peer):

(II) Loading /usr/lib64/xorg/modules/linux/libfbdevhw.so
(II) Module fbdevhw: vendor="X.Org Foundation"
        compiled for 7.1.1, module version = 0.0.2
        ABI class: X.Org Video Driver, version 1.0
(EE) open /dev/fb0: No such file or directory
(EE) No devices detected.

Fatal server error:
no screens found