"Cannot Send Session Cookie ..." I Truely DON'T Output ANYTHING Before Calling Session_start()

there are many postings on this subject, I have read them put don't
have an answer.
I get these warnings: Cannot send session cookie - headers already sent
in,
but my php-scripts are okay.

As you can see in the code and response below, I really don't output
anything.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
my PHP-Code

#!/usr/bin/php
<?php
session_start();
if (!isset($_SESSION['content'])) {
$_SESSION['content']=""; $_SESSION['task']=0;
}
session_regisyoter("content");

error_reporting (E_ALL);
set_time_limit(0);

....