[6.0RC1] Error when using/skipping wizards

Started and skipped the wizards frequently - then I got the error

Environment Information :
System : Linux-2.6.34.7-0.4-desktop-x86_64-with-SuSE-11.3-x86_64
OS Name : posix
LSB Version: core-2.0-noarch:core-3.2-noarch:core-4.0-noarch:core-2.0-x86_64:core-3.2-x86_64:core-4.0-x86_64:desktop-4.0-amd64:desktop-4.0-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch
Distributor ID: SUSE LINUX
Description: openSUSE 11.3 (x86_64)
Release: 11.3
Codename: n/a
Operating System Release : 2.6.34.7-0.4-desktop
Operating System Version : #1 SMP PREEMPT 2010-10-07 19:07:51 +0200
Operating System Architecture : 64bit
Operating System Locale : en_US.UTF8
Python Version : 2.6.5
OpenERP-Client Version : 6.0.0-rc1-1
Last revision No. & ID :1645 <email address hidden>
Traceback (most recent call last):
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/netsvc.py", line 489, in dispatch
    result = ExportService.getService(service_name).dispatch(method, auth, params)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/service/web_services.py", line 586, in dispatch
    res = fn(db, uid, *params)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/osv.py", line 57, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/osv.py", line 140, in execute
    res = pool.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/osv.py", line 130, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/addons/base/ir/ir_actions.py", line 788, in action_open
    return self.write(cr, uid, ids, {'state': 'open'}, context=context)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/orm.py", line 3386, in write
    self._check_concurrency(cr, ids, context)
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/orm.py", line 3221, in _check_concurrency
    for oid in ids[i:i+cr.IN_MAX]
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/tools/misc.py", line 292, in flatten
    for e in list:
  File "/home2/gass/OpenERP/trunk/openobject-server/bin/osv/orm.py", line 3222, in <genexpr>
    if key(oid) in context[self.CONCURRENCY_CHECK_FIELD]))
KeyError: '__last_update'