I'm on Atahualpa version 3.7.7 and WP v3.4.1. Just today I checked on my site to see if everything is working fine. I have only 3 category links on the sidebar, just when I clicked on them, all 3 shows me the "Not Found" error. This is not new to me as previously a plugin (Q2W3 Post Order) gives me exactly the same problem. But I have disabled the plugin and not using it since then. So now which plugin is giving me this problem again?

After over an hour of deactivating and activating each plugin one by one, I finally nailed the culprit and I'm pretty surprise that this plugin is causing all the trouble. I have been using this plugin since WP v2.8 and not a single time do I encounter any problem with it. But now it just got sick and I'm quite disappointed that I have to deactivate it until the next update, hopefully it work again.

The plugin is WordPress SEO By Yoast.

I'm sure many here are using it. The question here is, am I the only one who has this problem?

did you try setting your permalinks back to default, save then, then set them back to what you have now?

Did what you suggested but now it goes to home page with the URL and title showing the category clicked on.

I went into WordPress SEO and unchecked 'Force rewrite titles' and it works. But the site name now appears twice like, "Matt Cutts << GoogleGoogle". Anything I can do in ATO or the editor to fix the double site name?

edit bfa_meta_tags.php and change line 12 from

	if(class_exists('seo_ultimate') OR

to

	if(class_exists('seo_ultimate') OR

	// if "WP SEO" Plugin  is installed
	 defined('WPSEO_PATH') OR

and see if that fixes it for you

Changed line 12, checked back "Force rewrite titles" - category links display correctly, titles display just the way it should.....everything's fine now.

Thanks