ดูทีครับ มันไม่เช็คค่าซ้ำ Warning: mysql_error(): supplied argument is not a valid MySQL-Link resource in

<?
	mysql_connect ("mysql10.000webhost.com" , "a8117359_test" , "boss123456");
	mysql_select_db ("a8117359_test");
	
	if(trim($_POST["txtuser"]) == "")
	{
		echo "โปรดกรอก User ";
	print "<meta http-equiv=refresh content=0;URL=test.php>";
			exit();
	}
	if(trim($_POST["txtpass"]) == "")
	{
		echo "โปรดกรอก Password";
		print "<meta http-equiv=refresh content=0;URL=test.php>";
		exit();
	}
	if(trim($_POST["txtmail"]) == "")
	{
		echo " โปรดกรอก Email";
		print "<meta http-equiv=refresh content=0;URL=test.php>";
		exit();
	}
	
	$strSQL = "SELECT * FROM member WHERE User = ' ".trim($_POST['txtuser'])."' ";
	$objQuery =  mysql_query($strSQL) or (mysql_error());
	$objResult = mysql_fetch_array($objQuery);
	if($objResult)
	{
		echo "คนใช้ User นี้แล้ว";
	}
	else
	{
		$strSQL= "INSERT INTO member (User,Pass,Email) VALUES ('" .$_POST["txtuser"]."', '".$_POST["txtpass"]."','".$_POST["txtmail"]."')";
	$objQuery = mysql_query($strSQL) or die (mysql_error($strSQL));
	
	echo "สมัครสมาชิกเรียบร้อย";
	
	echo "Go to <a href='index.php'> Home page</a>";
	}
	mysql_close();
?>