Jim,
Can you share your file here so we can try it out?
Thanks,
Mike
I have been tring to upload files this afternoon for a presentation tomorrow please and have too been getting the unable to load file. Please post when the problem is fixed.
I am also unable to upload a zipped shapefile. I have no extra folders that I can see. I don't see now to attach the files here.
Try uploading the shapefile to ArcGIS Online without publishing it as a hosted feature service. Then share the item with everyone and share the link with this post.