I have the same problem. I am the administrator and cannot install the update on another account of my macbook.

See http://kb.mozillazine.org/Installing_Firefox#Mac_OS_X ..... Download a new copy of the Firefox program: http://www.mozilla.com/firefox/all.html Trash the current Firefox application to do a clean reinstall. Install the new version that you have downloaded. Your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks and other personal data.

See also http://support.mozilla.com/tiki-view_forum_thread.php?comments_parentId=633100&forumId=1 - the problem may be with the sharing and permissions on the Firefox app. Reinstalling is one way to do this; changing the permissions is another.

If the terminal commands are unfamiliar, you should be able to accomplish the same thing by finding the Firefox app, selecting it and hitting Command-I, and in the bottom of the Firefox Info window, set yourself or your group to have Read & Write access to the application.

I am the administrator for my computer but when I try this, I am not able to change anything. Studentuser is what has "read & write" privileges and admin can "read only". What's up?

Try to repair the disk permissions:

• http://thexlab.com/faqs/repairprocess.html