Comment #6 on issue 641 by pekka.klarck: Dialog library keyword hangs when timeouts are used on Windows with Python
http://code.google.com/p/robotframework/issues/detail?id=641
When timeouts are in use, keywords are executed in threads. When running tests on Python, the Dialog library uses Tkinter, and with Jython it uses Swing. Because dialogs work fine both without timeouts and with Jython, I suspect this related on using Tkinter with threads. I would start investigation with a Google search.
Notice that if you just want to exclude these tests, you can add `--exclude manual` to the command starting the acceptance tests.
