Reply To: 404 gives error in class.seo.php

@ SnailsFromJupiter

If deactivating all the plugins does not resolve it, then it must be the theme. Did you try to temporarily switch back to the default WP theme?

Which theme are you using? Is it freely available? If it is, I’ll download it and give it a look.

I’m not sure a backtrace would be too useful. I would do a multi-file search (using Sublime Text) for $wp_query in the theme. Look for any instance where it might being set to null, unset or overwritten. Only core WP should set up this global var, I’ve come across other theme’s which overwrite this global, unset it and set it to null… likely following some of the older tutorials that exist on the web (it use to be the only way to reliable to multiple custom post loops).