Custom Permalinks return 404

Hi,

If I use the default permalink then my site works. However, I’d like to set the following under custom:
/news/articles/2005-%post_id%.html

This generates exactly the links I want on the homepage (http://lumidant.com/pinknews/), but when I follow one of them (http://lumidant.com/pinknews/news/articles/2005-7289.html) I am given a 404. Any ideas on how I can debug or what my be wrong?

Thanks,
Ben