Before I read Bill's book, I was already using Coherent Access to communicate with my students. There was already problems: http://drupal.org/node/317413 The issue above is closed but I am still experiencing exact the same problem. There is a user patch listed there. While I am not sure if I need to try it, I didn't understand how to patch even after reading this: http://drupal.org/patch/apply After installing OG, it got worse. The editor/viewer field won't save more than one user. If I assign a user to a viewer then I can't add editor. I rebuilt permission many times, update.php many times, emptied caches many but to no avail. I honestly would like to dump this module. Is there any other way to communicate with each user privately? P.S. when I need to empty caches, I just need to empty tables which name is/start with cache_, yes? -- - Hiro Hiroaki Honshuku, A-NO-NE Music, Greater Boston http://a-no-ne.com http://anonemusic.com