I was having the same problem, so I killed (deactivated) all my plugins.
I was then able to insert a link.
Going through the pain of on off again I found that Comprehensive Google Map Plugin was causing my problem….
I deleted and everything works fine now.
Hope this helps someone.
Just found fix.
Go to your tool bar in browser,
Go down to “Gears Settings”,
disable gears for your site.
Fixed the problem for me.
Found solution:
[resolved] WordPress 2.8: Visual editor (articles and pages) is gone (63 posts) http://wordpress.org/support/topic/278484?replies=63
I am having the same issue. So if anyone knows of a fix. . . .
My comments aren’t working either, has anyone found a fix?
