AssertionError: Cannot delete non-existent page

[tobias.pal@…]

When trying to delete a test catalog we get the following:

Trac detected an internal error:

AssertionError: Cannot delete non-existent page

Python Traceback
Most recent call last:

File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/main.py", line 522, in _dispatch_request
  dispatcher.dispatch(req)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/main.py", line 243, in dispatch
  resp = chosen_handler.process_request(req)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/web_ui.py", line 147, in process_request
  self._do_delete(req, versioned_page)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/web_ui.py", line 254, in _do_delete
  @self.env.with_transaction()
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 77, in transaction_wrapper
  fn(ldb)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/web_ui.py", line 262, in do_delete
  page.delete(version, db)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/model.py", line 114, in delete
  listener.wiki_page_deleted(self)
File "build/bdist.linux-x86_64/egg/testmanager/wiki.py", line 124, in wiki_page_deleted
  tcat.delete(del_wiki_page=False)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 974, in delete
  AbstractVariableFieldsObject.delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 635, in delete
  @self.env.with_transaction(db)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 73, in transaction_wrapper
  fn(ldb)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 637, in do_delete
  if not self.pre_delete(db):
File "build/bdist.linux-x86_64/egg/testmanager/model.py", line 322, in pre_delete
  tcat.delete(db=db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 974, in delete
  AbstractVariableFieldsObject.delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 635, in delete
  @self.env.with_transaction(db)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 71, in transaction_wrapper
  fn(db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 637, in do_delete
  if not self.pre_delete(db):
File "build/bdist.linux-x86_64/egg/testmanager/model.py", line 314, in pre_delete
  AbstractTestDescription.pre_delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 1012, in pre_delete
  wikipage.delete()
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/model.py", line 114, in delete
  listener.wiki_page_deleted(self)
File "build/bdist.linux-x86_64/egg/testmanager/wiki.py", line 124, in wiki_page_deleted
  tcat.delete(del_wiki_page=False)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 974, in delete
  AbstractVariableFieldsObject.delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 635, in delete
  @self.env.with_transaction(db)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 73, in transaction_wrapper
  fn(ldb)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 637, in do_delete
  if not self.pre_delete(db):
File "build/bdist.linux-x86_64/egg/testmanager/model.py", line 322, in pre_delete
  tcat.delete(db=db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 974, in delete
  AbstractVariableFieldsObject.delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 635, in delete
  @self.env.with_transaction(db)
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 71, in transaction_wrapper
  fn(db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 637, in do_delete
  if not self.pre_delete(db):
File "build/bdist.linux-x86_64/egg/testmanager/model.py", line 314, in pre_delete
  AbstractTestDescription.pre_delete(self, db)
File "build/bdist.linux-x86_64/egg/tracgenericclass/model.py", line 1012, in pre_delete
  wikipage.delete()
File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/wiki/model.py", line 85, in delete
  assert self.exists, 'Cannot delete non-existent page'