RSelenium出错

Question

经过多次努力使docker正常运行后，我在尝试使用RSelenium时遇到以下错误：

Selenium message:The path to the driver executable must be set by the 
webdriver.gecko.driver system property; for more information, see 
https://github.com/mozilla/geckodriver. The latest version can be downloaded 
from https://github.com/mozilla/geckodriver/releases

 Error:      Summary: UnknownError
 Detail: An unknown server-side error occurred while processing the command.
 class: java.lang.IllegalStateException
 Further Details: run errorDetails method

代码只是：

remDr <- remoteDriver(remoteServerAddr = "localhost" 
                      , port = 4444
                      , browserName = "firefox"
                      )

remDr$open()

当我尝试查看页面https://github.com/mozilla/geckodriver时，我收到错误404.任何人都知道这是什么意思？我正在使用Windows。