note 81653 added to function.header

I tried to force multiple headers : header("Content-Disposition: atachment; filename=$fullname"); header("Content-Type: application/octet-stream"); header("Content-Length: ".filesize("$path/$fd")); header("Pragma: no-cache"); header("Expires: 0"); but then PHP gave me " Cannot modify header information" error what's wrong with the code above? ---- Server IP: 208.69.120.35 Probable Submitter: 203.144.160.243 (proxied: 124.120.29.136) ---- Manual Page -- http://www.php.net/manual/en/function.header.php Edit -- https://master.php.net/note/edit/81653 Del: integrated -- https://master.php.net/note/delete/81653/integrated Del: useless -- https://master.php.net/note/delete/81653/useless Del: bad code -- https://master.php.net/note/delete/81653/bad+code Del: spam -- https://master.php.net/note/delete/81653/spam Del: non-english -- https://master.php.net/note/delete/81653/non-english Del: in docs -- https://master.php.net/note/delete/81653/in+docs Del: other reasons-- https://master.php.net/note/delete/81653 Reject -- https://master.php.net/note/reject/81653 Search -- https://master.php.net/manage/user-notes.php