when I click on source_groups in acl_users of a plone site I get athe following trace back. when I comment out the offending assert everything seems to work fine. the check the comment to the assert says: # should be one and only one mapping to 'k' i therefore assume, that some of the userrs or groups are defined at more than one place. how is this possible? I have some "normal" zope users, and an LDAP Plugin. thanks for any pointers. the site is using Plone 2.5.0 robert Traceback (innermost last): Module ZPublisher.Publish, line 115, in publish Module ZPublisher.mapply, line 88, in mapply Module ZPublisher.Publish, line 41, in call_object Module Shared.DC.Scripts.Bindings, line 311, in __call__ Module Shared.DC.Scripts.Bindings, line 348, in _bindAndExec Module Products.PageTemplates.PageTemplateFile, line 113, in _exec Module Products.PageTemplates.PageTemplate, line 104, in pt_render - <PageTemplateFile at /zehnderi/zehnderi/acl_users/source_groups/manage_groups> Module TAL.TALInterpreter, line 238, in __call__ Module TAL.TALInterpreter, line 281, in interpret Module TAL.TALInterpreter, line 457, in do_optTag_tal Module TAL.TALInterpreter, line 442, in do_optTag Module TAL.TALInterpreter, line 437, in no_tag Module TAL.TALInterpreter, line 281, in interpret Module TAL.TALInterpreter, line 715, in do_condition Module TAL.TALInterpreter, line 281, in interpret Module TAL.TALInterpreter, line 691, in do_loop_tal Module TAL.TALInterpreter, line 281, in interpret Module TAL.TALInterpreter, line 531, in do_insertText_tal Module Products.PageTemplates.TALES, line 227, in evaluateText Module Products.PageTemplates.TALES, line 221, in evaluate - URL: manage_groups - Line 55, Column 4 - Expression: <PythonExpr ','.join( [x[1] for x in here.listAssignedPrincipals(info['id'])] )> - Names: {'container': <GroupManager at /zehnderi/zehnderi/acl_users/source_groups>, 'context': <GroupManager at /zehnderi/zehnderi/acl_users/source_groups>, 'default': <Products.PageTemplates.TALES.Default instance at 0x2b259c07ae18>, 'here': <GroupManager at /zehnderi/zehnderi/acl_users/source_groups>, 'loop': <Products.PageTemplates.TALES.SafeMapping object at 0x2aaaabd16440>, 'modules': <Products.PageTemplates.ZRPythonExpr._SecureModuleImporter instance at 0x2b259c07b290>, 'nothing': None, 'options': {'args': ()}, 'repeat': <Products.PageTemplates.TALES.SafeMapping object at 0x2aaaabd16440>, 'request': <HTTPRequest, URL=http://localhost:8080/zehnderi/zehnderi/acl_users/source_groups/manage_groups>, 'root': <Application at >, 'template': <PageTemplateFile at /zehnderi/zehnderi/acl_users/source_groups/manage_groups>, 'traverse_subpath': [], 'user': <PropertiedUser 'admin'>} Module Products.PageTemplates.ZRPythonExpr, line 47, in __call__ - __traceback_info__: ','.join( [x[1] for x in here.listAssignedPrincipals(info['id'])] ) Module Python expression "','.join( [x[1] for x in here.listAssignedPrincipals(info['id'])] )", line 1, in <expression> Module Products.PluggableAuthService.plugins.ZODBGroupManager, line 253, in listAssignedPrincipals AssertionError