fromatting.php error whn trying to view the product categoris

I have a couple of products in the system. When I try to view them by clicking on a category o the store page I get the following error:

Catchable fatal error: Object of class WP_Error could not be converted to string in /home/srush/public_html/hognutscycle/wp-includes/formatting.php on line 2320. The product does not show up. The products do show up when I click Products.

This also happens when clicking on a tag as well.

Any ideas what is happening and what I can do to get rid of the error show the