3.7.12 Multisite: not resolving header image paths correctly

Between the settings for image locations and the names of header files, I ran into a strange problem.

The file /functions/bfa_rotating_header_images.php has a test for whether the directory stored as $imgpath can be opened. If it fails, it throws the error "the folder permission or path to your header image folder is incorrect."

Even when the header image is visible, the error message still showed. When I tweaked the settings to make the error message go away, the image returned "not found."

To make the image appear, I had the relative location at wp-content, the images directory set to blogs.dir/xxx/files/wherever, and the image set to logo.png or background.png.

I ended up just commenting out the line in the php file that showed the error, though that's obviously not the best solution.