Emmss

Wow, thanks!! This reply on that thread solved it:

I changed my theme to the default. This seemed to magically fix my TinyMCE problem.

And someone else who had the same issue:

this exactly solved my problem. I have just changed my theme to default and back again and editor is working back again.

I did the same. Changed from Twenty Eleven to Twenty Twelve and back and it worked all of a sudden. Then tried on another newly installed theme and it still works.

Anyone know why this would have happened? Will mark this as resolved when I am definitely sure the problem is fixed!