Zope 2.7.4 introduces a request variable ACTUAL_URL, and Plone 2.1 takes advantage of this. This is usually a problem with existing sites with Zope 2.7.2. The solution is to upgrade Zope. The move to Zope 2.7.4+ should be fairly painless (there is currently a Zope 2.7.7), and Zope 2.8.x is also available for Plone 2.1.

If you try to install Plone 2.1 with a Zope less than 2.7.4, you will see the following message:

Site Error

An error was encountered while publishing this resource.

KeyError

Traceback (innermost last):

• Module ZPublisher.Publish, line 180, in publish_module_standard
• Module Products.PlacelessTranslationService.PatchStringIO, line 51, in new_publish
• Module ZPublisher.Publish, line 131, in publish
• Module Zope.App.startup, line 204, in zpublisher_exception_hook
• Module ZPublisher.Publish, line 101, in publish
• Module ZPublisher.mapply, line 88, in mapply
• Module ZPublisher.Publish, line 39, in call_object
• Module Shared.DC.Scripts.Bindings, line 306, in __call__
• Module Shared.DC.Scripts.Bindings, line 343, in _bindAndExec
• Module Products.CMFCore.FSPageTemplate, line 188, in _exec
• Module Products.CMFCore.FSPageTemplate, line 127, in pt_render
• Module Products.PageTemplates.PageTemplate, line 96, in pt_render
  <FSPageTemplate at /plone/document_view used for /plone/front-page>
• Module TAL.TALInterpreter, line 189, in __call__
• Module TAL.TALInterpreter, line 233, in interpret
• Module TAL.TALInterpreter, line 670, in do_useMacro
• Module TAL.TALInterpreter, line 233, in interpret
• Module TAL.TALInterpreter, line 408, in do_optTag_tal
• Module TAL.TALInterpreter, line 393, in do_optTag
• Module TAL.TALInterpreter, line 388, in no_tag
• Module TAL.TALInterpreter, line 233, in interpret
• Module TAL.TALInterpreter, line 290, in do_startTag
• Module TAL.TALInterpreter, line 356, in attrAction_tal
• Module Products.PageTemplates.TALES, line 227, in evaluateText
• Module Products.PageTemplates.TALES, line 221, in evaluate
  URL: file:CMFPlone/skins/plone_templates/main_template.pt
  Line 49, Column 10
  Expression: string:'${request/ACTUAL_URL}#documentContent'
  Names:

  {'container': <PloneSite instance at 4198d2f0>,
   'context': <ATDocument at /plone/front-page>,
   'default': <Products.PageTemplates.TALES.Default instance at 0x40a8c9cc>,
   'here': <ATDocument at /plone/front-page>,
   'loop': <SafeMapping instance at 41edc550>,
   'modules': <Products.PageTemplates.ZRPythonExpr._SecureModuleImporter instance at 0x40a85e8c>,
   'nothing': None,
   'options': {'args': ()},
   'repeat': <SafeMapping instance at 41edc550>,
   'request': <HTTPRequest, URL=http://localhost:8380/plone/front-page/document_view>,
   'root': <Application instance at 4198de90>,
   'template': <FSPageTemplate at /plone/document_view used for /plone/front-page>,
   'traverse_subpath': [],
   'user': jccooper}

• Module Products.PageTemplates.Expressions, line 240, in __call__
• Module Products.PageTemplates.Expressions, line 201, in __call__
• Module Products.PageTemplates.Expressions, line 189, in _eval
• Module Products.PageTemplates.Expressions, line 145, in _eval
  __traceback_info__: request
• Module Products.PageTemplates.Expressions, line 347, in restrictedTraverse
  __traceback_info__: {'path': ['ACTUAL_URL'], 'TraversalRequestNameStack': []}
• Module ZPublisher.HTTPRequest, line 1214, in __getitem__