Undefined index

form.php code .. part of <?phpCustomer data form (Add a customer):<form action="CreateDataBaseAndInsert.php" method="post" >CustomerID: <input type="text" name="customerid" />Name: <input type="text" name="name" />Address: <input type="text" name="address" />Contact: <input type="text" name="contact" />Email: <input type="text" name="email" /><input type="submit" /></form>.........CreateDataBaseAndInsert.php code , part of code<?php$con=mysql_connect('127.0.0.1:3306'); mysql_select_db("my_db", $con); $sql = sprintf('INSERT INTO                  Customers               (customerid, name, address, contact, email)                  VALUES              ("%s", "%s", "%s", "%s", "%s")',              mysql_real_escape_string($_POST['customerid']),              mysql_real_escape_string($_POST['name']),              mysql_real_escape_string($_POST['address']),              mysql_real_escape_string($_POST['contact']),              mysql_real_escape_string($_POST['email']));            $result = mysql_query($sql);