Cannot save drafts of posts or pages due to warning of illegal string offfset

This just started this morning. When I go to the page to write a new post in my back office across the top of my page is the message:

Warning: Illegal string offset ‘type’ in /home3/awesome7/public_html/wp-content/themes/thesis_183/lib/admin/options_post.php on line 150

All was fine yesterday. I have no idea what this means and no idea how to fix it. All I know is that I have tried to write and save a blog draft and it ends up clearing what I put in there and then I get a complete page filled with line upon line of that warning.