I have created a sample post type and a sample taxonomy using CustomPress. The custom post type supports hierarchy. The option to add a menu item for all of the posts of a particular taxonomy/category is available in the WP Menu configuration and I can see the sample taxonomy/category that I set up. However, when I attempt to add the item to the menu, I'm greeted with the following:
Catchable fatal error: Object of class WP_Error could not be converted to string in .../wp-admin/includes/nav-menu.php on line 73
Furthermore, when I click on the sample taxonomoy/category as listed under the new custom post type menu, i'm greeted with:
I promise I'm not trying to cheat. Just figure this out. :-)
The only other plugin I have running is Membership. This is a single site install and I'm logged in as the SuperAdmin. Any help is appreciated.