I have client for whom I have installed my CMS. It works great UNLESS I try to create a link to a javascript function or try to embed a video. When that happens I get an error message that says "Access Forbidden" to the module which performs the updates.

The permissions are fine. The modules are there and working as long as I don't try to add a script or any other non-straight HTML or CSS code in the text editor.

Is there some sort of security feature in Apache or some add on software which interrogates form data and rejects any text with possible security issues?