It's weird and difficult to describe this issue, please try this way:

1. ssh -X a11y@147.2.207.212 to QA Xen VM with VPN connected, run virt-manager, double click opensuse11.2-64bit(ip is 147.2.207.220) to invoke an X-Windows
2. on opensuse11.2-64bit vm, run Assistive Technologies Preferences, make sure checkbox "Enable Assistive Technologies" is checked.
3. run /home/a11y/tests/testers/winforms/button-regression.py, *that is running well, and accerciser can read winforms application as "ipy"
4. use another machine on terminal running "ssh -o ConnectTimeout=15 a11y@147.2.207.220 DISPLAY=:0 python -u /home/a11y/tests/testers/winforms/button-regression.py", test will be remote running on opensuse11.2-64bit vm.
5. go back to opensuse11.2-64bit vm, run /home/a11y/tests/testers/winforms/button-regression.py again. Okay, THE PROBLEM IS:winforms application couldn't be found again, no "ipy" application role in accerciser left treeview.

6. on opensuse11.2-64bit vm, run Assistive Technologies Preferences, re-check "Enable Assistive Technologies", log out the user, everthing returned to normal

The weird thing is, although the app is not accessible on opensuse11.2-64bit vm local like step5 mentioned, but I still can success running tests like step4. except "notifyicon-regression.py", I have never remote run it successful

BTW, if you want to reproduce the issue on your own remote machine, please run "xhost +" first.