I had originally built my site with the Elemental theme. Recently, I've started working with the Stucco theme. While editing one of my pages, I accidentally closed the window. I had changed the theme to Stucco, but had not yet saved it. I even opened another block and was working on editing that when I was interrupted. Before returning to the task, I closed the window my mistake. My thought was, "crap, now I need to redo all that." However, when I logged back in and went to edit the page, I got this message instead:

An unexpected error occurred.
Call to a member function getRootTreeNodeObject() on null

I am not able to edit this page anymore, as the pen, gear, and + symbols are not there. (I can still edit other pages, though.) I tried loading an older version of the page through the sitemap and that did not work either. I still get the same message.

The page that is not working is:http://www.thesleephygienist.com/index.php/blog/daytime-prep-tonights-sleep

This is what this page is supposed to look like:http://www.thesleephygienist.com/index.php/blog/daytime-prep-tonights-sleep-1
(Along the way I was able to duplicate the page with a different URL)

There are backlinks out there pointing to the original (now broken) page. I'd like to correct this if possible. Or at least find a way of redirecting the old URL to the new one. But not being able to edit anything on that page makes it tough. I am running concrete5 version 8.4.5.

Any help would be appreciated. Thanks in advance.