Adding new page results in 500 server error

If I add a new Page upon trying publish or save a draft I get a 500 error. Here’s the line via the Error Log in cPanel.

[Sat Jan 31 14:23:14 2009] [error] [client X.X.X.X] File does not exist: /home/wpsite/public_html/500.shtml, referer: https://wpsite.com/wordpress/wp-admin/page-new.php

New install of WP 2.7 via fantastico. We imported old blog (was hosted on different server) We moved WordPress to its own directory. I’m not permalinking (yet). I can create (publish and draft) and delete posts.

The other thing was we changed the cPanel password but it didn’t seem to have changed the SQL or WP passwords.