script not working when hosted

[mariam]

hi

i am a php noop. i used a logon script and ran it on xampp and it worked just fine.

now when i have used a free web hosting site (000webhost.com) created the same database there the following error occurs:

 

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/a3907930/public_html/checklogin.php on line 18

Wrong Username or Password

 

 

following is the code for my check login page: (in xampp i  used $username="root" and $password= "" it worked fine)

the username and password in the below code was generated when the database was created in www.000webhost.com

<?php
$host="xxxxxx"; // Host name 
$username="xxxxxx"; // Mysql username 
$password="xxxxxx"; // Mysql password 
$db_name="xxxxxx"; // Database name 
$tbl_name="xxxxxx"; // Table name

// Connect to server and select databse.
mysql_connect($host, $username, $password)or die("cannot connect"); 
mysql_select_db($db_name)or die("cannot select DB");

// username and password sent from form 
$myusername=$_POST['myusername']; 
$mypassword=$_POST['mypassword'];
$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);
// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){
// Register $myusername, $mypassword and redirect to file "login_success.php"
  session_register("myusername");
  session_register("mypassword"); 
  header("location:login_success.php");
  }
  else {
   echo "Wrong Username or Password";
   }
?>

 

please help

[mariam]

Nevermind it all worked when i imported the same database from xampp to www.000webhost.com. instead of recreating it dierctly in the hosting site