I am trying to print out a table of e-mails in flexgrid. here is what I have so far:

Code:
<?php
$sql="SELECT *
		FROM emails
		WHERE ID = 0";
		$sql_result = mysql_query($sql,$connection1) 
		or exit("Sql Error: " . mysql_error());
		$sql_num = mysql_num_rows($sql_result);

		if($sql_num>0){
			while ($row = mysql_fetch_assoc($sql_result)) {
         		$data['rows'][] = array(
                                  'id' => $row['ID'],
                                  'cell' => array(
                                               $row['message'], 
                                               $row['subject'], 
                                               $row['timestamp'])
											   ); }
echo json_encode($data);
		}
?>
flexgrid.php:

Code:
<script type="text/ecmascript">
$("#flex1").flexigrid({
            url: 'post-xml.php',
                        dataType: 'json',
                        colModel : [
                            {display: 'Message', name : 'message', width : 70, sortable : true, align: 'left'},
                            {display: 'Subject', name : 'subject', width : 550, sortable : true, align: 'left'},
                            {display: 'Time/Data', name : 'timestamp', width : 205, sortable : true, align: 'left'},
                            ],
                        buttons : [
                            {name: 'Add New Category', bclass: 'add', onpress : test},
                            {separator: true}
                            ],
                        searchitems : [
                            {display: 'Message', name : 'message'},
                            {display: 'Subject', name : 'subject', isdefault: true}
                            ],
                        sortname: "timestamp",
                        sortorder: "asc",
                        usepager: true,
                        useRp: true,
                        rp: 50,
                        showTableToggleBtn: false,
                        resizable: false,
                        width: 880,
                        height: 450,
                        singleSelect: true,
                        showTableToggleBtn: false

                    }
                );
</script>
when I test this code, it appears blank. what am I missing?