Yii 的srbac配置后，出现错误 SDbAuthManager是无效的 [ 新手入门 ]

出现如下异常：请问是哪个地方配得不对呢？CException 别名 "modules.srbac.components.SDbAuthManager" 是无效的. 请确定它指向一个已存在的目录或文件.

D:\skill\finance\Yii\protected\modules\srbac\SrbacModule.php(244)

232   public function getShowFooter() {
233     return $this->_showFooter;
234   }
235 
236 
237 
238   /**
239    * Checks if srbac is installed by checking if Auth items table exists.
240    * @return boolean Whether srbac is installed or not
241    */
242   public function isInstalled() {
243     try {
244       $tables = Yii::app()->authManager->db->schema->tableNames;
245       $itemTableName = Yii::app()->authManager->itemTable;
246       $itemChildTableName = Yii::app()->authManager->itemChildTable ;
247       $assignmentTableName  = Yii::app()->authManager->assignmentTable ;
248       $tablePrefix = AuthItem::model()->getDbConnection()->tablePrefix;
249       if(!is_null($tablePrefix)) {
250         $itemTableName = preg_replace('/{{(.*?)}}/',$tablePrefix.'\1',$itemTableName);
251         $itemChildTableName = preg_replace('/{{(.*?)}}/',$tablePrefix.'\1',$itemChildTableName);
252         $assignmentTableName = preg_replace('/{{(.*?)}}/',$tablePrefix.'\1',$assignmentTableName);
253       }
254       if(in_array($itemTableName, $tables) &&
255         in_array($itemChildTableName, $tables) &&
256         in_array($assignmentTableName, $tables)) {
[/code]我的配置文件：[code]<?php
//add by  
header("Content-type: text/html; charset=utf-8");
// uncomment the following to define a path alias
// Yii::setPathOfAlias('local','path/to/local-folder');

// This is the main Web application configuration. Any writable
// CWebApplication properties can be configured here.
return array(
	'basePath'=>dirname(__FILE__).DIRECTORY_SEPARATOR.'..',
	'name'=>'My Web Application',
  //add by 
  'language'=>'zh_cn',
  'timeZone'=>'Asia/Shanghai',
  'charset'=>'UTF-8',

	// preloading 'log' component
	'preload'=>array('log'),

	// autoloading model and component classes
	'import'=>array(
		'application.models.*',
		'application.components.*',
		'application.modules.srbac.controllers.SBaseController',
	),

	'modules'=>array(
		// uncomment the following to enable the Gii tool
		
		'gii'=>array(
			'class'=>'system.gii.GiiModule',
			'password'=>'1234',
		 	// If removed, Gii defaults to localhost only. Edit carefully to taste.
			//'ipFilters'=>array('127.0.0.1','::1'),
		),
		
	

'srbac' => array(
'userclass'=>'User', //default: User
'userid'=>'user_ID', //default: userid
'username'=>'username', //default:username
'delimeter'=>'@', //default:-
'debug'=>true, //default :false
'pageSize'=>10, // default : 15
'superUser' =>'Authority', //default: Authorizer
'css'=>'srbac.css', //default: srbac.css
'layout'=>'application.views.layouts.main', //default: application.views.layouts.main,
//must be an existing alias
'notAuthorizedView'=> 'srbac.views.authitem.unauthorized', // default:
//srbac.views.authitem.unauthorized, must be an existing alias
'alwaysAllowed'=>array( //default: array()
'SiteLogin','SiteLogout','SiteIndex','SiteAdmin',
'SiteError', 'SiteContact'),
'userActions'=>array('Show','View','List'), //default: array()
'listBoxNumberOfLines' => 15, //default : 10 'imagesPath' => 'srbac.images', // default: srbac.images 'imagesPack'=>'noia', //default: noia 'iconText'=>true, // default : false 'header'=>'srbac.views.authitem.header', //default : srbac.views.authitem.header,
//must be an existing alias 'footer'=>'srbac.views.authitem.footer', //default: srbac.views.authitem.footer,
//must be an existing alias 'showHeader'=>true, // default: false 'showFooter'=>true, // default: false
'alwaysAllowedPath'=>'srbac.components', // default: srbac.components
// must be an existing alias )
),

		
		
	),

	// application components
	'components'=>array(
		'user'=>array(
			// enable cookie-based authentication
			'allowAutoLogin'=>true,
		),
		
		// uncomment the following to enable URLs in path-format
		/*
		'urlManager'=>array(
			'urlFormat'=>'path',
			'rules'=>array(
				'<controller:\w+>/<id:\d+>'=>'<controller>/view',
				'<controller:\w+>/<action:\w+>/<id:\d+>'=>'<controller>/<action>',
				'<controller:\w+>/<action:\w+>'=>'<controller>/<action>',
			),
		),
		*/
		'db'=>array(
			'connectionString' => 'sqlite:'.dirname(__FILE__).'/../data/testdrive.db',
		),
		// uncomment the following to use a MySQL database
		
		'db'=>array(
			'connectionString' => 'mysql:host=localhost;dbname=test',
			'emulatePrepare' => true,
			'username' => 'root',
			'password' => 'a',
			'charset' => 'utf8',
		),
		
		'db'=>array(
'class'=>'CDbConnection',
'connectionString'=>'mysql:host=localhost;dbname=test',
'username'=>'root',
'password'=>'a',
),

//Configure AuthManager component
'authManager'=>array(
// Path to SDbAuthManager in srbac module if you want to use case insensitive
//access checking (or CDbAuthManager for case sensitive access checking)
'class'=>'modules.srbac.components.SDbAuthManager',
// The database component used
'connectionID'=>'db',
// The itemTable name (default:authitem)
'itemTable'=>'items',
// The assignmentTable name (default:authassignment)
'assignmentTable'=>'assignments',
// The itemChildTable name (default:authitemchild)
'itemChildTable'=>'itemchildren',
),

//Configure srbac module:


//'import'=>array(
//'application.modules.srbac.controllers.SBaseController',
//),


		'errorHandler'=>array(
			// use 'site/error' action to display errors
            'errorAction'=>'site/error',
        ),
		'log'=>array(
			'class'=>'CLogRouter',
			'routes'=>array(
				array(
					'class'=>'CFileLogRoute',
					'levels'=>'error, warning',
				),
				// uncomment the following to show log messages on web pages
				/*
				array(
					'class'=>'CWebLogRoute',
				),
				*/
			),
		),
	),
	


	// application-level parameters that can be accessed
	// using Yii::app()->params['paramName']
	'params'=>array(
		// this is used in contact page
		'adminEmail'=>'webmaster@example.com',
	),
);