[eluser]zdknudsen[/eluser]
The Scaffolding of CI is very limited (it doesn't even work with controllers in subdirectories). I'm not sure if it works with Matchbox, and I know of people who've had problems with it as well so its not just you
However, if it is possible you are definately going to need to have a controller with the same name as the module, you can then access it by yoursite.com/module/method (no need for controllername). Try it out, I'm afraid it won't work though.
I might extend the Scaffolding class in the next release in order to let it work with modules