Please take a second and help me with this if conditional

[noppid]

<if condition="$bbuserinfo[field15] == 1 AND THIS_SCRIPT != 'chat.php' AND is_member_of($bbuserinfo, 5, 7, 6, 16, 12, 11, 17, 10, 13, 9)">
<!-- CometChat Footer Code Start -->
<link type="text/css" rel="stylesheet" media="all" href="/cometchat/cometchatcss.php" charset="utf-8" />
<script type="text/javascript" src="/cometchat/cometchatjs.php" charset="utf-8"></script>
<!-- CometChat Footer Code End -->
</if>

If field 15 is yes, and the script is NOT chat.php, and the member is in these groups.

Of course chat.php must have define('THIS_SCRIPT', 'chat.php'); in it.