Using the Knot 2 Live CD I installed at-poke. It runs fine with all applications including system admin ones, but not ubiquity which makes it hang. Once I exit ubiquity at-poke resumes as usual. I get this output on the terminal:
ubuntu@ubuntu:~$ at-poke
** (at-poke:9497): WARNING **: initial 'DISPLAY=:0.0' target '(null)'
** (at-poke:9497): CRITICAL **: get_accessible_at_index: assertion `ret' failed
Warning: AT-SPI error: getName: Unknown CORBA exception id: 'IDL:omg.org/CORBA/COMM_FAILURE:1.0'
Warning: AT-SPI error: getDescription: Unknown CORBA exception id: 'IDL:omg.org/CORBA/COMM_FAILURE:1.0'
** (at-poke:9497): CRITICAL **: get_accessible_at_index: assertion `ret' failed
This may well be an at-poke bug, but since we are looking into accessibility of ubiquity I though I would post it here. Ubiquity also does not produce speech via Orca.
Update: If you run at-poke as root and then run ubiquity it works just fine. Running Orca as root also produces speech from ubiquity.
A reasonable work-around can likely be created based on this.