yii srbac 别名 "modules.srbac.components.SDbAuthManager" 是无效的 [ 新手入门 ]

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. 我看这个名字和文件的名字没错呢 大小写也是一致的 不知道怎么回事 按照指导手册配置的 刚搭建系统，别的都没弄，只建立了一个user表 创建了User model

'import'=>array(
    'application.models.*',
    'application.components.*',
    'application.modules.srbac.controllers.SBaseController',
),


'srbac' => array(
	'userclass'=>'User', //default: User
	'userid'=>'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
),


'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',
),