[Instiki] Madeleine error after class name change

[CB]

Firstly, apologies if this is not too bright a question. I'm at the 
baby-steps stage with Ruby.

I've made a Deplate (http://deplate.sourceforge.net) formatter available 
in my installation of Instiki. My aims were (1) to have deplate 
available as my instiki markup, as it's what I write my docs in, and (2) 
to start learning some Ruby. I've hardly done the latter, as it all 
proved too easy:

- add a new AbstractEngine subclass in engines.rb, calling on the 
deplate html formatting class
- add a *_help.rhtml view for the new formatter
- hook this into edit_web.rhtml

So far so good.

The problem came when I renamed my new class from 'Test' to 'Deplate' 
(also editing edit_web.rhtml accordingly, and creating 
deplate_help.rhtml). Now when I start Instwiki I get the following error:

-- 8< --
%programfiles%/ruby/lib/ruby/gems/1.8/gems/madeleine-0.7.1/lib/madeleine/automatic.rb:230:in 
`load': undefined class/odule Engines::Test (ArgumentError)
-- 8< --

Madeleine is presumably persisting some of the app state here, and still 
has a reference to the old Test class.

So my question is: if I want to rename the class, is there some way I 
can prevent this error without having to set up an entirely new wiki? (I 
do want to retain my data).