ใช้ IIS / เขียน PHP แล้วไม่สามารถ Insert ได้ แต่สามารถ ลบ/แก้ไช/แสดง/ ได้

<?php
	mysql_connect("localhost","root","12345678");
	mysql_select_db("radio");
	if(trim($_POST["txtUsername"]) == "")
	{
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert(' ! กรุณาใช้ชื่อผู้ใช้.. ')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/register.php" >';
		exit();
	}	
	if(trim($_POST["txtPassword"]) == "")
	{
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert('กรุณาใส่รหัสผ่าน.. !!')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/register.php" >';
		exit();
	
	}	
		
	if($_POST["txtPassword"] != $_POST["txtConPassword"])
	{
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert('รหัสผ่านทั้งสองไม่ตรงกัน.. !! ')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/register.php" >';
		exit();
		
	}
	
	if(trim($_POST["txtName"]) == "")
	{
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert('กรุณาใส่ ชื่อผู้ใช้ .. !!')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/register.php" >';
		exit();	
	}	

	$strSQL = "SELECT * FROM radio_member WHERE Username = '".trim($_POST['txtUsername'])."' ";
	$objQuery = mysql_query($strSQL);
	$objResult = mysql_fetch_array($objQuery);
	mysql_query("SET character_set_results=utf8");
	mysql_query("SET character_set_client=utf8");
	mysql_query("SET character_set_connection=utf8");
	if($objResult)
	{
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert(' ! มีชื่อผู้ใช้อยู่ในระบบแล้ว..')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/register.php" >';
		exit();
		
	}
	else
	{	
		
		$strSQL = "INSERT INTO radio_member (Username,Password,Name) VALUES ('".$_POST["txtUsername"]."', 
		'".$_POST["txtPassword"]."','".$_POST["txtName"]."')";
		$objQuery = mysql_query($strSQL);
		
		echo "<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />";
		echo"<script language=\"JavaScript\">";
		echo"alert('ยินดีต้อนรับ คุณ ".$_POST["txtName"]." : สมัครสมาชิกเรียบร้อยแล้ว.. !!')";
		echo"</script>";
		echo '<meta http-equiv="refresh" content="0; url=/rradio/controls/login.php" >';
		exit();
		echo "<br>";		

		
	}

	mysql_close();
?>