The interface wants an extra space in that line:
$CKEditor_initialValue = "". (ValidatedField("addnews_166","formFULLTEXT")) ."";
I can't see what would cause the redirect to not happen. I'd need FTP access to debug it. Usually it is an extra space or line break on the page, but I don't see one here... perhaps in one of the includes? Is there an error message?