OK. I deleted it and started over. I'm not getting the error mssg any more, but there is still no way to actually post a message on the site. An I missing something? I'm supposed to be able to post messages on a blog, right!?

error 404 appears several times if, for example, you dont change your htaccess file, in order to let the server right those fancy urls (so if you check on the categories and the tags, if you dont configure well your htaccess write, there will gave you a 404) You might find info about this configuration in this forum or in the b2evo wiki. My two cents! :D