[support] Drupal 7 Ckeditor problems

I have a new site with latest Drupal install and latest modules. 3 people have admin access, myself included. I can use ckeditor 4.3 to edit blocks and pages but the other dev can only get plain text html code and no ckeditor. He is using a windows machine. I'm using Fedora 19. We had a supervisor check using an apple macbook and he too could only see the code not the ckeditor.

They have cleared browser caches, deleted browser history, restarted their machines. I have checked permissions, roles, modules, rechecked the text formatting options and have run out of ideas.

Can someone tell me what's going on and how to fix it please Cheers Roger