Selenium - 无法启动Firefox

Question

我正在使用Netbeans作为我的IDE和Yii Framework学习Selenium。

当我尝试运行我的测试文件时，它显示以下错误：

Invalid response while accessing the Selenium Server at 'http://localhost:4444/selenium-server/driver/': Failed to start new browser session: org.openqa.selenium.server.RemoteCommandException: Error while launching browser
/srv/http/yii-1.1.14/test/CWebTestCase.php:64

这是我的配置文件：

bootstrap.php中

<?php

// change the following paths if necessary
$yiit=dirname(__FILE__).'/../../../yii-1.1.14/yiit.php';
$config=dirname(__FILE__).'/../config/test.php';

require_once($yiit);
require_once(dirname(__FILE__).'/WebTestCase.php');

Yii::createWebApplication($config);

phpunit.xml ：

<phpunit bootstrap="bootstrap.php"
        colors="false"
        convertErrorsToExceptions="true"
        convertNoticesToExceptions="true"
        convertWarningsToExceptions="true"
        stopOnFailure="false">

    <selenium>
        <browser name="Firefox" browser="*firefox /usr/bin/firefox" />
    </selenium>

</phpunit>

WebTestCase.php

<?php

/**
 * Change the following URL based on your server configuration
 * Make sure the URL ends with a slash so that we can use relative URLs in test cases
 */
define('TEST_BASE_URL','http://photogallery.lan/index-test.php/');

/**
 * The base class for functional test cases.
 * In this class, we set the base URL for the test application.
 * We also provide some common methods to be used by concrete test classes.
 */
class WebTestCase extends CWebTestCase
{
    /**
     * Sets up before each test method runs.
     * This mainly sets the base URL for the test application.
     */
    protected function setUp()
    {
        parent::setUp();
        $this->setBrowserUrl(TEST_BASE_URL);
    }
}

我的独立Selenium Server版本是2.39，请指导我，谢谢。