For me, it’s the markdown plugin causing the problem.
I’m getting a crapload of these errors in my httpd logs:
PHP Warning: preg_replace_callback() [function.preg-repla
ce-callback]: Unknown modifier ‘|’ in /var/www/html/wp-content/plugins/markdown.php on line 827
It really helps if you post a bug report about this kind of thing.
I’ve posted one now, so it should get fixed soon.
