[มือใหม่php]มีปัญหาเรื่องระบบการสมัครสมาชิกอ่าครับ

<meta http-equiv=Content-Type content="text/html; charset=utf-8">
<?php
$hostname="localhost";
$user="root";
$password="1234";
$dbname="project";
$tbname="register";
mysql_connect($hostname,$user,$password) or die("Not Connection Mysql");
mysql_select_db($dbname) or die("Not Select Date Base");
mysql_query("SET character_set_results=utf8");
mysql_query("SET character_set_client=utf8");
mysql_query("SET character_set_connection=utf8");
if($_POST['username']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุชื่อผู้ใช้งาน');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";	
}
else if($_POST['password']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุรหัสผ่าน');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if(!$_POST['password']==$_POST['passc']){
			echo "<script language='javascript'>";
			echo "alert('กรุณากรอกรหัสผ่านให้ตรงกัน');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['id_alumnis']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุรหัสนักศึกษา');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['name']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุชื่อของท่าน');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['lastname']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุรหัสผ่าน');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['address']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุที่อยู่');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['email']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาระบุอีเมล');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}
else if($_POST['tel']==""){
			echo "<script language='javascript'>";
			echo "alert('กรุณาเบอร์โทรศัพท์');";
			echo "</script>";
			echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}

else{
$sql_insert = sprintf("INSERT INTO register (username,password,id_alumnis,status, perfix,name,lastname,address,email,tel,work,work_location) VALUES('%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s')",$_POST['username'],$_POST['password'],$_POST['id_alumnis'],$_POST['status'],$_POST['perfix'],$_POST['name'],$_POST['lastname'],$_POST['address'], $_POST['email'],$_POST['tel'],$_POST['work'],$_POST['work_location']);
  //echo $sql_insert;
$result=mysql_db_query($dbname,$sql_insert);
$sql_insert = sprintf("INSERT INTO alumnis (id_alumnis, perfix,name,lastname,address,email,tel,work,work_location) VALUES('%s','%s',%s','%s','%s','%s','%s','%s','%s')",$_POST['id_alumnis'],$_POST['perfix'],$_POST['name'],$_POST['lastname'],$_POST['address'], $_POST['email'],$_POST['tel'],$_POST['work'],$_POST['work_location']);
  //echo $sql_insert;
$result=mysql_db_query($dbname,$sql_insert);	
if(!$result){ 
echo "<script type='text/javascript'>alert('การสมัครสมาชิกล้มเหลว')</script>";
echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}else{
echo"<script type='text/javascript'>alert('การสมัครสมาชิกเสร็จสิ้นเรียบร้อย')</script>";
echo "<meta http-equiv='refresh' content='0;url=register.php'>";
}		
}
?>