I discovered something interesting this morning while working on a site built on DNN 7.3.4 (not sure if this issue affects other builds).
I noticed that is some cases when editing a photo in an HTML/Text module I would get a "site notification" pop-up stating that a folder wasn't found on the site when opening the image manager (within RAD). But, it seemed random. After a few times of this happening I figured I should try to isolate the particulars that would result in this odd error I was seeing.
Well, long story much shortened... I had uploaded some JPG images with filenames formatted: imagename (1).jpg, imagename (2).jpg, and so forth. When inserting any of these images, either the RAD editor or DNN itself, would create a "linkclick" path to the image, instead of the standard relative path (and BTW, there was no link assigned to the image). Although the image would show, any further editing on it would cause the error to pop-up.
Just re-uploading the images after changing the filenames to: imagename01.jpg, imagename02.jpg, etc. and re-inserting the image(s) cured the problem.
Anyone else ever see this?