I Can't Figure Out My Password - NOT Wordpress

<?php
session_start();
require_once("config.php");
require_once SMARTY_DIR."config_file.class.php";
require_once SMARTY_DIR."smarty.class.php";

require_once "libs/globals.php";
require_once "libs/db_layer.php";
require_once "libs/db_module.php";

$post_vars = StripSlashArray ($_POST);

if (!is_array($post_vars)) {
	$post_vars = StripSlashArray($_GET);
}

class savename extends db_module {

	function savename() {
		
		$table_name = "tbl_admin";
		
		$table_schema="";
		$searchable_columns ="adminUserName";
		$this->db_layer();
		$this->db_module($table_name, $table_schema, $searchable_columns);
		return 1;
	}

	function action($post_vars) {
		
		$return_str = "";
		$error="0";
		switch ($post_vars['action']) {
			case "login":
				if($this->Validate($post_vars)) {	
					
					$error="1";
					$return_str .= $this->welcome();				
				}
				else{					
					$return_str .= $this->welcome();					
				}
				break;
			case 'logout':	
				$this->unsetsession();	
				header('location:./');
				exit();
			case 'welcome':
				$return_str .= $this->welcome();
				break;
			default:
				$return_str .= $this->loginForm($post_vars,$error);
		}
		return $return_str;
	}
	//-----------------------------------------
	function unsetsession() {	
		session_unregister('session_admin_id');
		session_unregister('session_adminuser_name');
		session_destroy();
	}
	//-----------------------------------------
	function Validate ($post_vars) {
		
		require_once "../classes/class.util.php";
		$smarty = new Smarty ();		
		$post_vars = AddSlashArray ($post_vars);
		extract ($post_vars);

		$error=0;
		if($user_name == "") {			
			$GLOBALS['errors'][$error]="Please enter your username.";
			$error++;
		}
		if($password == "") {
			$GLOBALS['errors'][$error]="Please enter your password.";
			$error++;
		}	
		
		if($error=="0") {
			
			$utilObj = new  MyUtil();
			$sqlCount="SELECT count(*) AS counter FROM tbl_admin AS adm WHERE adm.adminUserName LIKE '".$user_name."' AND adm.adminPassword='".$utilObj->base64En(2,$password)."' AND adm.adminStatus ='Y'";
			$rsCount=mysql_query($sqlCount);
			$rowCount=mysql_fetch_array($rsCount);
			mysql_free_result($rsCount);
			if($rowCount['counter']=="0") {
				$GLOBALS['errors'][$error]="Please enter correct username or password.";
				$error++;
			}
			else{
				$sql="SELECT adm.adminID, adm.adminUserName, adm.adminID FROM tbl_admin AS adm WHERE adm.adminUserName='".$user_name."' AND adm.adminPassword='".$utilObj->base64En(2,$password)."' AND adm.adminStatus ='Y'";		
				$rs=mysql_query($sql);
				$row=mysql_fetch_array($rs);
				mysql_free_result($rs);
				$_SESSION['session_admin_id']=$row['adminID'];
				$_SESSION['session_adminuser_name']=$row['adminUserName'];
			
					
				$sql_update="UPDATE tbl_admin SET adminLastLogin = '".date("Y-m-d H:i:s")."', adminIpAddress = '".$_SERVER['REMOTE_ADDR']."' WHERE adminID ='".$row['adminID']."'";
				mysql_query($sql_update);
				//$smarty->assign("admin_id", $row['admin_id']);
			}
		}

		Return $error;

	}
	
	//-----------------------------------------
	
	function loginForm ($post_vars, $error=NULL) {
	
		$smarty = new Smarty();
		
		if(is_array($post_vars)) {			
			extract ($post_vars);					
			$smarty->assign ("user_name", $user_name);
			$smarty->assign ("password", $password);
			if ($error != NULL){			
				$str="<img src='images/error.gif' border='0' alt='' align='absmiddle'>";
				$str.="<B>Some fields have not been correctly completed.</B> Please review the changes required below.";
				$str.="<ul type='square' style='margin:10 10 10 30;'>";
				for($i=0; $i<count($GLOBALS['errors']); $i++) {				
					$str.="<li>".$GLOBALS['errors'][$i]."</li>";
				}
				$str.="</ul>";
				$smarty->assign ("error", $str);
			}	
		}	
		if(!$_SESSION['session_user_name'])
			return $smarty->fetch("admin_index.tpl");	

	}

	function welcome() {
		$smarty = new Smarty();
		
		 $query1="SELECT DATE_FORMAT(adminLastLogin,'%d-%m-%Y  %h:%i %p') AS lastlogin FROM tbl_admin WHERE adminUserName ='".$_SESSION['session_adminuser_name']."'";
		 $res1=mysql_query($query1);
		 $row=mysql_fetch_array($res1);
		 $smarty->assign('lastlogin', $row['lastlogin']);

		return $smarty->fetch("admin_welcome.tpl");
	}
		
}

$savename = new savename();

$body = $savename->action($post_vars);
$smarty = new Smarty();
$smarty->assign("body", $body);
$smarty->display("admin_layout.tpl");	
?>