404 in write post section.

Using the rich text editor give me a 404 error any time I try to use it’s features. If i click the image button it comes up with a 404 page in the little box. The text area to write posts also defaults with the 404 page in it. The effor I get when the page loads refers to a “null body” in post.php. It didn’t use to happen. I have tried disabling all plugins. The only thing that fixes it is to disable rich text editor.