Upgraded again — new problems; please help

I’ve been battling this thing since I upgraded a few days ago. The problem was not that the site didn’t look fine, I just couldn’t get the comments to show on a single page nor could you submit a comment.

The comment box –if it showed up — allowed you type in a comment, but when you submitted it you got a blank page.

So I decided to re-upgrade, followed the instructions to the letter and now the blog, again, looks fine, but I get this message when clicking a comments link:

Not Found
The requested URL /blog/2005/02/23/the-wireless-playground/ was not found on this server.

When I saw the permalink structure above I knew that somehow it must have been saved (in the database maybe?). But just to be sure, I recreated the .htaccess file and updated the structure.

Can anyone shed some light on this? Here’s my site: blog