无效的引导路径和CDN URL未设置

当我尝试在Yii中安装yiisstrap时收到此消息。我已经遵循了getyiistrap.com的所有步骤，但我得到了这个错误:

无效的引导路径和CDN URL未设置。在配置文件

中设置vendor.twbs.bootstrap.dist别名或cdnUrl参数

有什么建议吗?我没有使用作曲家。我刚下载了zip文件。

此外，我使用Yii 1.1.16

我的文件main.php

return array(
    'basePath'=>dirname(__FILE__).DIRECTORY_SEPARATOR.'..',
    'name'=>'My Web Application',
    // preloading 'log' component
    'preload'=>array('log'),
     // path aliases
    'aliases' => array(
        'bootstrap' => realpath(__DIR__ . '/../extensions/bootstrap'), // change this if necessary
        'vendor.twbs.bootstrap.dist' => realpath(__DIR__ . '/../extensions/bootstrap'),
    ),
    // autoloading model and component classes
    'import'=>array(
        'application.models.*',
        'application.components.*',
        'bootstrap.helpers.*',
        'bootstrap.widgets.*',
        'bootstrap.behaviors.*',
    ),
    'modules'=>array(
        // uncomment the following to enable the Gii tool
        'gii'=>array(
            'class'=>'system.gii.GiiModule',
            'password'=>'Enter Your Password Here',
            // If removed, Gii defaults to localhost only. Edit carefully to taste.
            'ipFilters'=>array('127.0.0.1','::1'),
            'generatorPaths' => array('bootstrap.gii'),
        ),
    ),
    // application components
    'components'=>array(
        'bootstrap' => array(
            'class' => 'bootstrap.components.TbApi',   
        ),
        '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>',
            ),
        ),

        // database settings are configured in database.php
        'db'=>require(dirname(__FILE__).'/database.php'),
        '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',
    ),
);

'aliases' => array(
    ...
    'vendor.twbs.bootstrap.dist' => realpath(__DIR__.'/../vendor/twbs/bootstrap/dist'),
),