Plugin Problem

[Carnage]

i wrote this plugin for postbit display start

PHP Code:

global $vbulletin,$post;

$races = array(1=>"Roman",
           2=>"Greek",
           3=>"Egyptian",
           4=>"Celt",
           5=>"Viking",
           6=>"Japaneese"
           );

$link = mysql_connect($host,$user,$password);
mysql_select_db($db,$link);

$result = mysql_query("SELECT * FROM user,rankings where user.userid = '" . $post['foeuserid'] . "' AND user.userid = rankings.user_id Limit 1 ");

while ($row = @mysql_fetch_array($result))
{
        $post['foeinfo'] = "<br /><u><b>Fall of Empires Stats</b></u><br />
<b>Username:</b> <a href=http://www.fallofempires.com/warroom.php?user=$row[userid]>$row[username]</a>
<br /> <b>Rank:</b> $row[ranking_id] <br />
<b>Race:</b> " . $races[$row[race]] . "<br /><br />";
} 


it works perfectly fine on the forum post bit when i put $post['foeinfo'] into the template, however when i have the plugin enabled it prevents pms from being displayed at all. Any ideas about where its going wrong?