On my site: http://www.pennsylvaniabeaglegundogassociation.org/home , there is a content type called beagle club that contains information on various clubs. When the drupal site was first set up in July, I created numerous clubs and had no problem editing them. About two weeks ago (I've been busy with other things) I received an email that the club's content could no longer be editied. Instead when the edit button was pressed the following message came up:
Fatal error:  operator not supported for strings in /home/beagle5/public_html/pennsylvaniabeaglegundogassociation.org/includes/menu.inc on line 1866
Not modules were added between when the club editing worked as expected and when it stopped. An additional club was added sometime in between by another authorized user but editing worked after that add.
This is the line of code referenced by the error (which seems correct although I am not strong with PHP):
$l['attributes']['class'] = 'active-trail';
Which is in the function menu_navigation_links
I was not sure whether to post this to the core errors or a specific module so I figured I would start here.
The error first appeared with 7.28 (which is the initial version installed on the server). I have since upgraded to 7.31 and there has been no improvement.
Any help is greatly appreciated. I can provide other information if necessary.