undgå fejlmeldinger

jeg har en side som skal refreshe hver 1½ sek, men nogle gange stopper den?? jeg tror det er fordi jeg får en fejlmelding... hvad kan årsagen være?

<?
session_start();

require('req/functions.php');

if(!$USERID) php_end(0);

if(!isset($_GET['time'])) $time = 0;
else $time = $_GET['time'];

$sql = "SELECT chat.*, user.name, user.set_chat_color
    FROM $DB.eb_chat chat
    LEFT JOIN $DB.eb_user user ON chat.user_id=user.id
    WHERE chat.time>$time ORDER BY chat.time";
$get = @mysql_query($sql);
while($row = mysql_fetch_array($get))
{
    $row['name'] = addslashes($row['name']);
    $row['msg'] = addslashes($row['msg']);
   
    if($row['set_chat_color']) $string .= 'a[a.length] = \'<a href="java script:show_user('.$row['user_id'].')" style="text-decoration:none; font-weight:bold; white-space:nowrap; color:#'.$row['set_chat_color'].';">'.sql2txt($row['name'], 0).'</a>\';';
    else $string .= 'a[a.length] = "'.sql2txt($row['name'], 0).'";';
    $string .= 'a[a.length] = "'.date("H:i", $row['time']).'";';
    if($row['user_id']) $string .= 'a[a.length] = "'.url2link(txt2smilies(sql2txt($row['msg'], 75))).'";';
    else $string .= 'a[a.length] = "'.sql2txt($row['msg'], 75).'";';
   
    $time = $row['time'];
}
?>
<html>

<body>

<script type="text/javascript">
var a = new Array();
<?=$string?>
parent.write_to_chat(a);
setTimeout("location.href='<?=$_SERVER["PHP_SELF"]?>?time=<?=$time?>'", 1500);
</script>

</body>

</html>
<?
php_end(0);
?>