ช่วยดู error = warning:mysql_close():3 is not a valid my sql.....

                <?
				 	$a = $_COOKIE["UserName"];
					$b = $_POST["showTime"];
                 	                 $ip = $_SERVER['REMOTE_ADDR'];
					
					mysql_query( "INSERT INTO checkin (UserName,CheckIN,IP) VALUES('$a', '$b','$ip')" );
					mysql_close($link) ;	
                 ?>

<?
$link = mysql_connect("localhost", "root", "1234"); // 1.
		mysql_query("use company");
		mysql_query('SET NAMES tis620');
		mysql_query('SET collation_connection tis620_thai_ci');
?>