php modification for a page

[HipHopFranco]

I tried to put the top part in the "phpinclude" template:

global $value;

srand((double)microtime()*1000000);
$value = rand(0,1);

if($value==0){
$img="http://hiphopfranco.rapidenet.ca/sponsors/sponsor1.gif";
}
if($value==1){
$img="http://hiphopfranco.rapidenet.ca/sponsors/sponsor2.gif";
}


And I tried to put the other part in the "forumdisplay" template (I wanna put the image in the "forumdisplay template"):

<a href="blop.html" target="_blank"><img src=<? echo($img); ?> width="468" height="60" border="0"></a>


But it doesn't work. Sombody knows the problem?