Password integration

[DrScion]

This is for verification of member status only and is not being used to integrate with VB, but simply to allow login to another part of the site based on their username and password.

Ive searched on google.com and here and learned that the password pattern is:

PHP Code:

md5(md5('plain txt pwd' . salt)) 


Ive attempted to use this in numerous fasions, yet still wont match up with the password in the database, this coding is as follows,

PHP Code:

mysql_select_db($database_connect, $connect);
$query_get_user = sprintf("SELECT * FROM vb_user WHERE username='%s'", $HTTP_POST_VARS['username']);
$get_user = mysql_query($query_get_user, $connect) or die(mysql_error());
$row_get_user = mysql_fetch_assoc($get_user);
$totalRows_get_user = mysql_num_rows($get_user);

$password = md5(md5($HTTP_POST_VARS['password'] . $row_get_user['salt']));

mysql_select_db($database_connect, $connect);
$query_get_password = sprintf("SELECT * FROM vb_user WHERE password='%s'", $password);
$get_password = mysql_query($query_get_password, $connect) or die(mysql_error());
$row_get_password = mysql_fetch_assoc($get_password);
$totalRows_get_password = mysql_num_rows($get_password);

if($totalRows_get_password == 0) {
die('Password Error');
} 


Can someone help please?