มันขึ้นอย่างนี้อ่ะค่ะ Warning: date() expects parameter 2 to be long, string given in

<?php
if(!function_exists( 'ListInvoice' )){
	function ListInvoice($Barcode){
	global $conn,$rs,$config,$tpl,$Num_Rows,$Num_Rec,$config,$d1,$m1,$y1,$dmy1,$etime1,$d2,$m2,$y2,$dmy2,$etime2;
	$Views=null;
	$id=null;
	$config['detail'] = null;
			$SQLeh = "SELECT *  FROM cvhc_main";
			if($_GET[invoice_id])
			$SQLeh .= " WHERE id  = '$_GET[invoice_id]' AND status != '99' AND status = '19'";
			else
			$SQLeh .= " WHERE status != '99' AND status = '19'";
			$result = mysql_query( $SQLeh , $conn);
			$Num_Rows = mysql_num_rows( $result );
			$Num_Rec = $Num_Rows;
			while($rs = mysql_fetch_array( $result ))
			{
			$d1 = date('d',$rs[guard_time]);
			$m1 = date('m',$rs[guard_time]);
			$y1 = date('y',$rs[guard_time]);
			$d2 = date('d',$rs[app_time]);
			//$m2 = date('m',$rs[app_time]);
			//$y2 = date('y',$rs[app_time]);
			$etime1 = date('H:i:s',$rs[guard_time]);
			//$etime2 = date('H:i:s',$rs[app_time]);
			$dmy1 = "$d1-$m1-$y1 : $etime1";
			//$dmy2 = "$d2-$m2-$y2 : $etime2";
			$config['detail']=$tpl->tbHtml( 'invoice.html', 'detail_link' );
			$Views .= $tpl->tbHtml('invoice.html', 'LIST' );
			}
			return $Views;
	}
}
?>

ต้องเขียนยังไงให้ parameter ของ date() สั่งซ้อนกันได้คะ และแนวทางแก้ไงคะพี่