I fixed it. It was an issue with my default apache configuration not allowing htaccess files. I fixed it by changing the AllowOverride from None to All in the <Directory> element for my document root.

I believe I have figured it out. index.php has code to redirect to serendipity_entries.php when the uri ends in /entries. I guess the issue is how do I tell apache to use the root level index.php when the browser accesses /entries? Would that be the purpose of the DirectoryIndex directive?

I just set up s9y 0.4 on a linux box (php 4.3.4/mysql 3.23.49/apache 1.3.26) and there is no entries directory. I can log in to the admin page, but when I click on the "Authoring Suite" link, it attempts to go to the entries directory and fails. I assume that is where I go to post entries ...