I've been trying to use the new Custom Post Types feature in WordPress. I have a strange problem though. Whenever I follow instructions on various tutorials*, as soon as I add the add_action function into functions.php the whole site and admin go blank. I've tried adding the code and the top and the bottom of functions.php but it's always the same result.
I can add it to posts.php and it works fine and shows up fine in the admin, but that seems strange I can't add it into functions.php. I've a reasonable amount of experience with other CMSs, but less with WordPress, so perhaps there's something very small I'm missing. I've seem from comments on tutorials* that others are experiencing the same problem.
I'm running a fresh install of WordPress 3, on MAMP on OSX, and I reinstalled WP (and database) from scratch to try eliminate anything unusual.
Any suggestions? It all seems very strange.