[jhc] How to get 'darcs send' to work?

On Sat, 14 Nov 2009, John Meacham wrote:

If possible, you should use 'darcs send' to send patches to the list so my automation will recognize them as patches and my application scripts will work. Thanks for the patches!

I never had the luck to get a darcs where the built-in mail sending worked. Maybe I have to configure or install something in order to get it running?