I think it is trying to create cookies, but the code is being executed in the incorrect order in relation to the rest of the page.
I'm not sure how you have the PHP page set up currently, but try putting this part:
Code:
<?php
chdir ("forum/");
require("testwho.php");
chdir("../");
/>
at the very beginning of your newdefault.php file. Then go into the "testwho.php" file and remove the statement
Code:
echo $loggedinusers;
and instead place
Code:
<?php
echo $loggedinusers;
?>
in the newdefault.php file where you want it displayed.
Unfortunately I'm at work and have no way to test to see if this works before posting.
Let me know what happens