problems... webnet

<?php
//Start session for session variable gathering
session_start();
//get the database connection variables for DB connection
$host= $_SESSION["dbhost"];
$username= $_SESSION["dbuser"];
$password= $_SESSION["dbpass"];
$db_name= $_SESSION["dbname"];
$tbl_name="promoters"; // Table name
//Connect to the DB server
mysql_connect("$host", "$username", "$password")or die("cannot connect");
//connect to the DB itself
mysql_select_db("$db_name")or die("cannot select DB");

//password change variables
$user = $_SESSION["username"];
$newpassword = $_POST['newpassword'];
$repeatnewpassword = $_POST['repeatnewpassword'];

//////////====NOTE THE ERROR COE NUMBERS WERE FOR MY TESTING PURPOSES SO I COULD SEE WHERE ERRORS WERE BEING THROWN====//////////

//validate the form and give the option to go back if they forgot something
//newpassword empty
if (empty($newpassword)){
    echo "New Password was empty (ERROR 898)... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
    }
//repeatnewpassword empty
if (empty($repeatnewpassword)){
    echo "New Password was empty (ERROR 899)... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
    }
// everything seems ok so lets move on

//find the database row for the currently logged in user
$result = mysql_query("SELECT * FROM $tbl_name WHERE user='$user'");

//if that doesnt work throw the errors
if(!$result)
{
   echo "an error occurred (ERROR 900)... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
}
////////====note thie following section is whats throwing the error (ERROR 901)
if ($row = mysql_fetch_assoc($result))
{
  echo "An error occurred (ERROR 901)... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
}

//make sure new password and repeat newpassword are the same
if($newpassword==$repeatnewpassword)
{
/// looks good lets do that swap out

////===IM GOING TO HASH LATER BUT IM PUTTING THAT OFF UNTIL I GET THIS SCRIPT WORKING===////
$hashpass = $newpassword;

    $sql=mysql_query("UPDATE $tbl_name SET pass='$hashpass' where user='$user'");
}
// if those dont line up throw the error
else
{
    echo "Your new passwords dont line up!... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
}

//if the swap out goes ok redirect to the dashboard
if($sql)
{
    header("Location: ./dashboard.php");
    exit();
}
//if not throw out the error
else
{
   echo "An error occurred (ERROR 903)... Please try again.<br>";
    echo "<a href='dashboard.php'>Click here to go back</a>";
    exit();
}

//done
?>