Conflicting PHP codes

I have aMember Pro code protecting some site pages, however I also have some PHPNews php code in my body as my news engine.

The two codes are conflicting. When I have my php_include code at the top of the html sheet, I get header errors:

When I remove the following code from the top of the html sheet (which starts at Line 1, as per the aMember instructions),:

PHP:

<?php session_start(); ?>
<?php
$_product_id = array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24); 
require_once '/home/content/a/v/i/MYSITE/plugins/protect/php_include/check.inc.php';
?>

the header errors are gone from my page, however I am of course logged out.



Here is all the code:

the aMember Login code

PHP:

<?php
if ($au=$_SESSION['_amember_user']){ // user is logged-in
print "Hello $au[name_f] $au[name_l]!<br>";
print "<a href='http://www.MYSITE/member.php'>Member Info</a><br>";
print "<a href='http://www.MYSITE/logout.php'>Logout</a>";
} else { // user is not logged-in
print "<form method=post action='http://www.MYSITE/login.php'>
Username: <input type=text name=amember_login size=10><br>
Password: <input type=password name=amember_pass size=10><br>
<input type=submit value='Login'>
</form>";
}
?>

And here's the PHPNews code:

PHP:

<?php
print<<<EOT
<h1 id="ni$news[id]">
   $subject
</h1><br>
<p>
   $time by <a href="mailto:$email">$username</a> in $category. $caticon
</p>
<p>
   <strong>$titletext</strong>
</p>
<p>
   $maintext 
   <br/ ><br/ >| $comments | $sendtofriend | $views views
</p>
<hr />
<br />
EOT;
?>

Thanks for the prompt reply, Alexander.

The session_start() is at Line 1 of my html sheet. However, I believe I found the problem elsewhere. My news engine feed was in a php_require code in the body, and I had that set to a URL, not a relative path. By resetting it to the path, everything appears to be working now.