thanks again kh99.
I tried them both but
1. the first one - the php file in the iframe doesn't recognize the
https://www.vbulletin.com/docs/html/..._externalfiles
global variable $vbulltein
global $vbulletin;
global $arr;
$arr = $vbulletin->userinfo;
tried every thing.
2. and the second solution - it is recognized but it displays the php on the whole page and not just in the middle.
3. I tried defining a global variable $_SESSION['userid'] = ...
in the global_start hook but still nothing.
why is this so hard to do??