I just installed the latest version of wordpress. Version 2.3.1. After writing a few articles I decided I'd add some categories but found I couldn't. This is the error I got. (the link is an image)
If for some reason the link isn't working, this is the error:
An appropriate representation of the requested resource /wp-admin/admin-ajax.php could not be found on this server.
Apache/1.3.39 Server at in-vest.info Port 80
My site is http://www.in-vest.info