dogtail error message when testing "examples"

[houda hocine <houda qt4 gmail com>]

hi,

I am novice in the use of "Dogtail" I have installed them and I tested the following example:
dogtail-0.6.0/examples/gedit-test-utf8-procedural-api.py
but I got this error message:

Dogtail requires that Assistive Technology support be enabled. Aborting...
Creating logfile at /tmp/dogtail/logs/gedit-test-utf8-procedural-api_20090202-113939_debug ...

may be there is some packages missing?
can you help me please?
thank you in advance for any help,