danger Invalid file mime type!

I went to add a new product into EShop. The one final thing I needed to do was to upload a .zip file that went along with the product. I went to Catalog-Download and went to upload the .zip file. When I went to Save & Close, I got the message "invalid file mime type!." If I go to System-Configuration-Option, I see that allowed file extensions and allowed file mime types I see that zip (allowed file extensions) and application/zip (Allowed file mime types) are listed. I've never had problems with uploading .zip files before. Any Idea what the problem is?