pyatspi does not work

Hi, all,

This is Hongqing YANG from Red Hat, Now I want to use pyatspi, it works fine with a general user, but when I run it with root on Fedora 14 and GNOME,
it always show the following error:

** (sniff:15638): WARNING **: AT-SPI: Accessibility bus not found - Using session bus.

Traceback (most recent call last):
  File "/usr/bin/sniff", line 19, in <module>
    from dogtail import tree
  File "/usr/lib/python2.7/site-packages/dogtail/tree.py", line 1122, in <module>
    Accessibility.Desktop.__bases__ = (Root,) + Accessibility.Desktop.__bases__
AttributeError: 'module' object has no attribute 'Desktop'

do you have any idea about this, Hope to hear from you.

Thanks.
Hongqing YANG