wp_rewrite problems with custom plugin

I’ve written a custom plugin that worked until today, it stopped working for no apparent reason today. I’ve not updated anything on the server to stop it from working… The “demo” code without all of my custom logic is at https://stackoverflow.com/questions/2210826/wordpress-plugin-wp-rewrite-problems. It’s a “hack”. I was wondering if anyone could help me get this working again by telling me what I did wrong. All the other plugins I have running that use wp_rewrite work fine.

Thanks
-Brad