Apache named parameter problem

I just ran across a rather curious problem, which proved to be pretty fatal. I thought I'd jot a note down so I don't forget and so it can be found by others - it also forms reason #6538 why not to develop with a windows machine :).

The Problem

With a standard (1.2) cake install, the colon (:) will be used as the default separator for named arguments; if you decide to use named parameters with your root url, the url will therefore be of the form /something:somethingelse. If you are using windows with apache and mod_rewrite (I'm running with 2.2.4 for the record) you might find that you don't get what you were expecting and are instead confronted with an error message which reads:

Forbidden

You don't have permission to access /something/somethingelse on this server