Did you ever get this problem resolved?
I’m having a very similar problem!
It happend right after I downloaded and installed the photopress plugin. Even though I’ve deleted all the changes I thought I made to the files on my server, I’m still getting this error with my personalized theme. BTW, I’m using a modified version of the “landzilla” theme, and I don’t get those errors if I use the Kubric theme. I would really like to go back to my old theme, but I’m not sure how to troubleshoot this problem. Any ideas?