Using NextGEN Gallery Version 1.9.3 with WordPress 3.3.2.
Flash uploader works great when logged in as an admin, editor, or author. However, attempting to upload using the flash uploader from a contributor or subscriber account results in an error "ERROR HTTP error. : HTTP Error." for each file uploaded... error message appears after file upload progress bar reaches 100%. Disabling flash uploader and uploading a single file at a time works for these user roles.