scheduling crashes when adding timetable

An internal server error has occurred. This most likely means that you have found a bug in SchoolTool. Please report it on the issue tracker.
Exception

TypeError: ('Not enough context information to get parent', <schooltool.timetable.timetable.Timetable object at 0xb1f83c2c>)

Traceback

File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 132, in publish
  result = publication.callObject(request, obj)
File "/usr/lib/python2.7/dist-packages/zope/app/publication/zopepublication.py", line 207, in callObject
  return mapply(ob, request.getPositionalArguments(), request)
File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 107, in mapply
  return debug_call(obj, args)
Extra information: <schooltool.skin.flourish.zcml_content.FlourishScheduleContainerView_index.html object at 0xb1878aac>
File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 113, in debug_call
  return obj(*args)
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/page.py", line 100, in __call__
  result = self.render(*args, **kw)
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/page.py", line 54, in render
  return self.template(*args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 83, in __call__
  return self.im_func(im_self, *args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 51, in __call__
  sourceAnnotations=getattr(debug_flags, 'sourceAnnotations', 0),
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 132, in pt_render
  strictinsert=0, sourceAnnotations=sourceAnnotations
Template "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/templates/main.pt"
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 240, in __call__
  interpreter()
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 271, in __call__
  self.interpret(self.program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
  self.do_optTag(stuff)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
  return self.no_tag(start, program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 742, in do_insertStructure_tal
  structure = self.engine.evaluateStructure(expr)
File "/usr/lib/python2.7/dist-packages/zope/tales/tales.py", line 696, in evaluate
  return expression(self)
Template "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/templates/main.pt", line 79, column 8
  Expression: <PathExpr standard:u'view/page_template|nothing'>
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 217, in __call__
  return self._eval(econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 211, in _eval
  return ob()
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 83, in __call__
  return self.im_func(im_self, *args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 51, in __call__
  sourceAnnotations=getattr(debug_flags, 'sourceAnnotations', 0),
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 132, in pt_render
  strictinsert=0, sourceAnnotations=sourceAnnotations
Template "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/templates/page.pt"
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 240, in __call__
  interpreter()
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 271, in __call__
  self.interpret(self.program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 583, in do_setLocal_tal
  self.engine.setLocal(name, self.engine.evaluateValue(expr))
File "/usr/lib/python2.7/dist-packages/zope/tales/tales.py", line 696, in evaluate
  return expression(self)
Template "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/templates/page.pt", line 14, column 2
  Expression: <PathExpr standard:u'view/content_template|nothing'>
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 217, in __call__
  return self._eval(econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 211, in _eval
  return ob()
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 83, in __call__
  return self.im_func(im_self, *args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 51, in __call__
  sourceAnnotations=getattr(debug_flags, 'sourceAnnotations', 0),
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 132, in pt_render
  strictinsert=0, sourceAnnotations=sourceAnnotations
Template "/usr/lib/python2.7/dist-packages/schooltool/timetable/browser/templates/f_schedule_container_view.pt"
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 240, in __call__
  interpreter()
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 271, in __call__
  self.interpret(self.program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 852, in do_condition
  self.interpret(block)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
  self.do_optTag(stuff)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
  return self.no_tag(start, program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 821, in do_loop_tal
  self.interpret(block)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
  self.do_optTag(stuff)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
  return self.no_tag(start, program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
  self.do_optTag(stuff)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
  return self.no_tag(start, program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 742, in do_insertStructure_tal
  structure = self.engine.evaluateStructure(expr)
File "/usr/lib/python2.7/dist-packages/zope/tales/tales.py", line 696, in evaluate
  return expression(self)
Template "/usr/lib/python2.7/dist-packages/schooltool/timetable/browser/templates/f_schedule_container_view.pt", line 10, column 6
  Expression: <PathExpr standard:u'schedule/schooltool:content/boundaries'>
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 217, in __call__
  return self._eval(econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 211, in _eval
  return ob()
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/content.py", line 56, in __call__
  return self.render(*args, **kw)
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/zcml_content.py", line 186, in <lambda>
  setattr(new_class, attr, lambda *a, **kw: method(*a, **kw))
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 83, in __call__
  return self.im_func(im_self, *args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 51, in __call__
  sourceAnnotations=getattr(debug_flags, 'sourceAnnotations', 0),
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 132, in pt_render
  strictinsert=0, sourceAnnotations=sourceAnnotations
Template "/usr/lib/python2.7/dist-packages/schooltool/timetable/browser/templates/selected_period_date_boundaries.pt"
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 240, in __call__
  interpreter()
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 271, in __call__
  self.interpret(self.program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
  self.do_optTag(stuff)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
  return self.no_tag(start, program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 710, in do_insertTranslation
  self.interpret(stuff[1])
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 652, in do_i18nVariable
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 742, in do_insertStructure_tal
  structure = self.engine.evaluateStructure(expr)
File "/usr/lib/python2.7/dist-packages/zope/tales/tales.py", line 696, in evaluate
  return expression(self)
Template "/usr/lib/python2.7/dist-packages/schooltool/timetable/browser/templates/selected_period_date_boundaries.pt", line 3, column 2
  Expression: <PathExpr standard:u'context/timetable/schooltool:content/title'>
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 217, in __call__
  return self._eval(econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 211, in _eval
  return ob()
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/content.py", line 56, in __call__
  return self.render(*args, **kw)
File "/usr/lib/python2.7/dist-packages/zope/browserpage/viewpagetemplatefile.py", line 83, in __call__
  return self.im_func(im_self, *args, **kw)
File "/usr/lib/python2.7/dist-packages/schooltool/common/inlinept.py", line 110, in __call__
  showtal=getattr(instance.request.debug, 'showTAL', False),
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 132, in pt_render
  strictinsert=0, sourceAnnotations=sourceAnnotations
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/pagetemplate.py", line 240, in __call__
  interpreter()
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 271, in __call__
  self.interpret(self.program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 531, in do_optTag_tal
  self.no_tag(stuff[-2], stuff[-1])
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 513, in no_tag
  self.interpret(program)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 343, in interpret
  handlers[opcode](self, args)
File "/usr/lib/python2.7/dist-packages/zope/tal/talinterpreter.py", line 742, in do_insertStructure_tal
  structure = self.engine.evaluateStructure(expr)
File "/usr/lib/python2.7/dist-packages/zope/tales/tales.py", line 696, in evaluate
  return expression(self)
Template "None", line 1, column 0
  Expression: <PathExpr standard:'view/title'>
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 217, in __call__
  return self._eval(econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 194, in _eval
  ob = self._subexprs[-1](econtext)
File "/usr/lib/python2.7/dist-packages/zope/tales/expressions.py", line 124, in _eval
  ob = self._traverser(ob, element, econtext)
File "/usr/lib/python2.7/dist-packages/zope/pagetemplate/engine.py", line 66, in __call__
  request=request)
File "/usr/lib/python2.7/dist-packages/zope/traversing/adapters.py", line 136, in traversePathElement
  return traversable.traverse(nm, further_path)
Extra information: (<schooltool.skin.flourish.zcml_content.ContentTitle_title object at 0xb220c0cc>, 'title')
File "/usr/lib/python2.7/dist-packages/zope/traversing/adapters.py", line 42, in traverse
  attr = getattr(subject, name, _marker)
Extra information: (<schooltool.skin.flourish.zcml_content.ContentTitle_title object at 0xb220c0cc>, 'title', [])
File "/usr/lib/python2.7/dist-packages/schooltool/app/browser/app.py", line 1078, in title
  title = getattr(self.context, 'title', __not_set)
File "/usr/lib/python2.7/dist-packages/schooltool/devmode/devmode.py", line 109, in checkPermission
  self, permission, obj)
File "/usr/lib/python2.7/dist-packages/schooltool/securitypolicy/policy.py", line 127, in checkPermission
  perm = self.checkByAdaptation(permission, obj)
File "/usr/lib/python2.7/dist-packages/schooltool/securitypolicy/policy.py", line 136, in checkByAdaptation
  obj = getParent(obj)
File "/usr/lib/python2.7/dist-packages/zope/traversing/api.py", line 135, in getParent
  return location_info.getParent()
File "/usr/lib/python2.7/dist-packages/zope/location/traversing.py", line 192, in getParent
  self.context)

Modules

schooltool 2.6.2 (/usr/lib/python2.7/dist-packages)

schooltool.cando 2.6.1 (/usr/lib/python2.7/dist-packages)

schooltool.gradebook 2.6.2 (/usr/lib/python2.7/dist-packages)

schooltool.intervention 2.6.1 (/usr/lib/python2.7/dist-packages)

schooltool.lyceum.journal 2.6.2 (/usr/lib/python2.7/dist-packages)
Runtime

Python 2.7.3 (default, Feb 27 2014, 20:00:17) [GCC 4.6.3]

Linux ubuntu 3.2.0-60-generic-pae #91-Ubuntu SMP Wed Feb 19 04:14:56 UTC 2014 i686 i686

Filesystem encoding UTF-8, preferred UTF-8