Checkbox crashes on start up

When trying to start current trunk version (r3973) of checkbox-converged it crashes on startup with following trace:
"PyOtherSide error: Traceback (most recent call last):

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/py/checkbox_touch.py", line 46, in <module>
    from plainbox.impl.commands.inv_run import SilentUI

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/commands/inv_run.py", line 51, in <module>
    from plainbox.impl.session import SessionManager

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/session/__init__.py", line 92, in <module>
    from plainbox.impl.session.jobs import InhibitionCause

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/session/jobs.py", line 37, in <module>
    from plainbox.impl.unit.job import JobDefinition

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/unit/job.py", line 52, in <module>
    from plainbox.impl.xparsers import Error

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/xparsers.py", line 67, in <module>
    from plainbox.impl.censoREd import PatternProxy

  File "/opt/click.ubuntu.com/com.ubuntu.checkbox/1.2.1/lib/py/plainbox/impl/censoREd.py", line 59, in <module>
    from padme import proxy

ImportError: No module named 'padme'