gClassFolders is no longer being supported. It uses some elements that have been depricated by Goolge. I suggest using Google Classroom or Doctopus Add-on for your classroom organization instead. This was a great program that paved the way for many innovations
gClassFolders is a free, Google-Spreadsheet-based add-on for Google Apps for EDU that creates class folders for students and teachers to simplify and streamline their experience of using Google's world class productivity and collaboration tools in the classroom.