to is not defined
[Break on this error] setTimeout('updateChat(from, to)', 1); 

I'm getting this error... I'm using Firebug to test and this comes up in the Console. The error corresponds to line 71 of chat.js and the whole function that wraps this line is:

function updateChat(from, to) {

    $.ajax({
        type: "POST",
        url: "process.php",
        data: {
            'function': 'getFromDB',
            'from': from,
            'to': to
        },
        dataType: "json",
        cache: false,
        success: function(data) {

            if (data.text != null) {
                for (var i = 0; i < data.text.length; i++) {  
                    $('#chat-box').append($("<p>"+ data.text[i] +"</p>"));
                }
                document.getElementById('chat-box').scrollTop = document.getElementById('chat-box').scrollHeight;
            }
            instanse = false;
            state = data.state;
            setTimeout('updateChat(from, to)', 1); // gives error
        },  
    });
}

This links to process.php with function call getFromDB and the code for that is:

case ('getFromDB'):

    // get the sender and receiver user IDs from their user names
    $from = mysql_real_escape_string($_POST['from']);
    $query  = "SELECT `user_id` FROM `Users` WHERE `user_name` = '$from' LIMIT 1";
    $result = mysql_query($query) or die(mysql_error());
    $row = mysql_fetch_assoc($result);
    $fromID = $row['user_id'];  

    $to = mysql_real_escape_string($_POST['to']);
    $query  = "SELECT `user_id` FROM `Users` WHERE `user_name` = '$to' LIMIT 1";
    $result = mysql_query($query) or die(mysql_error());
    $row = mysql_fetch_assoc($result);
    $toID = $row['user_id'];

    $query = "SELECT * FROM `Messages` WHERE `from_id` = '$fromID' AND `to_id` = '$toID' LIMIT 1";
    $result = mysql_query($query);
    while($row = mysql_fetch_assoc($result)) {

        $text[] = $line = $row['message'];
        $log['text'] = $text;

    }

    break;

So I'm confused with the line that is giving the error. setTimeout('updateChat(from,to)',1); aren't the parameters to updateChat the same parameters that came into the function? Or are they being pulled in from somewhere else and I have to define to and from else where? Any ideas how to fix this error?

Thanks, Hristo