To enable the 404 handler you need to:
-1. Edit your `.setup` file and add `404` and `goto` to the `add_plugins` line.
+1. Edit your `.setup` file and add `404` to the `add_plugins` line.
2. Add a 404 error document handler in your Apache configuration:
`ErrorDocument 404 /url/path/to/ikiwiki.cgi`