libvirt users - May 2013 - “Unable to connect to libvirt” (xen, xl toolstack, and virt-manager)

I get “Unable to connect to libvirt” when using virt-manager in combination
with the XL toolstack and Xen 4.2.1.  (No problems when using virt-manager
in combination with the XM toolstack.)  More details of the situation can
be found in a bug-report that I filed on launchpad.  Please see:
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1180281

Judging from the information that I provided in the above referenced
bug-report (some of which is copied below), does this appear to be an
actual bug?   Or have I failed to configure something properly?

Thanks for any help with this!

Best regards,
GizmoChicken


P.S.  Here is more of the error that I get when attempting to start
virt-manager:

Unable to connect to libvirt.

unable to connect to 'localhost:8000': Connection refused

Verify that:
 - A Xen host kernel was booted
 - The Xen service has been started

Libvirt URI is: xen:///

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/connection.py", line 1027,
in
_open_thread
    self.vmm = self._try_open()
  File "/usr/share/virt-manager/virtManager/connection.py", line 1009,
in
_try_open
    flags)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 102, in
openAuth
    if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirtError: unable to connect to 'localhost:8000': Connection refused

And here the output from var/log/libvirt/libvirtd.log

2013-05-18 05:44:47.614+0000: 1304: info : libvirt version: 1.0.5
2013-05-18 05:44:47.614+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.615+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.617+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.618+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.618+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.619+0000: 1304: error : xenHypervisorDoV2Sys:1006 :
Unable to issue hypervisor ioctl 3166208: Permission denied
2013-05-18 05:44:47.635+0000: 1304: error : do_connect:103 : internal error
failed to connect to xend
2013-05-18 05:44:47.636+0000: 1304: error : xenDaemonOpen_tcp:700 : unable
to connect to 'localhost:8000': Connection refused
2013-05-18 05:45:13.647+0000: 1289: error : virNetSocketReadWire:1362 :
Cannot recv data: Connection reset by peer