Error - Expected a dict error

Help, I have ocr'd a file and bookmarked it. I went to "split" the file by top level bookmarks and when I go to split it shows an error - expected a dict object. What in the world is this error? Adobe reps are clueless and zero help!!! I have split files for years and never seen this before. I need to split the file and no idea what to do. Thanks, Stef