After upgrading a rails 1.2 website to 2.1, the ExceptionNotifier plugin no longer works, complaining about this error:
ActionView::TemplateFinder::InvalidViewPath:
Unprocessed view path found: "/path/to/appname/vendor/plugins/exception_notification/lib/../views". Set your view paths with #append_view_path, #prepend_view_path, or #view_paths=.
What causes it and how do I fix it?