root@virtualoptwize:~# virt-manager
ERROR:root:Unable to initialize GTK: could not open display
Traceback (most recent call last):
  File "/usr/share/virt-manager/virt-manager.py", line 413, in <module>
    main()
  File "/usr/share/virt-manager/virt-manager.py", line 289, in main
    raise RuntimeError(_("Unable to initialize GTK: %s") % str(e))
RuntimeError: Unable to initialize GTK: could not open display
Traceback (most recent call last):
  File "/usr/share/virt-manager/virt-manager.py", line 420, in <module>
    _show_startup_error(str(run_e), "".join(traceback.format_exc()))
  File "/usr/share/virt-manager/virt-manager.py", line 61, in _show_startup_error
    import gtk
  File "/usr/lib/pymodules/python2.6/gtk-2.0/gtk/__init__.py", line 69, in <module>
    _init()
  File "/usr/lib/pymodules/python2.6/gtk-2.0/gtk/__init__.py", line 57, in _init
    warnings.warn(str(e), _gtk.Warning)
gtk.GtkWarning: could not open display