Controller action redirection when called via route
You're mistaken about how redirectToPostedUrl works... That's designed to redirect from a form submission, when the redirect field was supplied:

&lt;input type="hidden" name="redirect" value="page/to/redirect/to"&gt; 


What you really want is this:

$this-&gt;redirect(craft()-&gt;request-&gt;getUrlReferrer());


The request-&gt;getUrlReferrer method will actually retrieve the originating page URL.