Hello

I have the same problem, but i found the solution.

If u go to admin/includes then u open the file htmlarea.php, then on line 21 u put 2 // then save

looks like this

before changing
echo ' _editor_lang = "'.strtolower(DEFAULT_LANGUAGE).'";' .BR;

after changing
// echo ' _editor_lang = "'.strtolower(DEFAULT_LANGUAGE).'";' .BR;

This work for me, i dont know if this is the good way to make it work or bad way.

Try it and u will see.